summaryrefslogtreecommitdiff
path: root/aircraft_cmd.c
blob: 0e1f6f4b76415601455107a8358fd0ea77eac057 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
/* $Id$ */

#include "stdafx.h"
#include "openttd.h"
#include "debug.h"
#include "functions.h"
#include "table/strings.h"
#include "map.h"
#include "tile.h"
#include "vehicle.h"
#include "depot.h"
#include "engine.h"
#include "command.h"
#include "station.h"
#include "news.h"
#include "sound.h"
#include "player.h"
#include "airport.h"
#include "vehicle_gui.h"
#include "table/sprites.h"

static bool AirportMove(Vehicle *v, const AirportFTAClass *Airport);
static bool AirportSetBlocks(Vehicle *v, AirportFTA *current_pos, const AirportFTAClass *Airport);
static bool AirportHasBlock(Vehicle *v, AirportFTA *current_pos, const AirportFTAClass *Airport);
static bool AirportFindFreeTerminal(Vehicle *v, const AirportFTAClass *Airport);
static bool AirportFindFreeHelipad(Vehicle *v, const AirportFTAClass *Airport);
static void AirportGoToNextPosition(Vehicle *v, const AirportFTAClass *Airport);
static void CrashAirplane(Vehicle *v);

static void AircraftNextAirportPos_and_Order(Vehicle *v);
static byte GetAircraftFlyingAltitude(const Vehicle *v);

static const SpriteID _aircraft_sprite[] = {
	0x0EB5, 0x0EBD, 0x0EC5, 0x0ECD,
	0x0ED5, 0x0EDD, 0x0E9D, 0x0EA5,
	0x0EAD, 0x0EE5, 0x0F05, 0x0F0D,
	0x0F15, 0x0F1D, 0x0F25, 0x0F2D,
	0x0EED, 0x0EF5, 0x0EFD, 0x0F35,
	0x0E9D, 0x0EA5, 0x0EAD, 0x0EB5,
	0x0EBD, 0x0EC5
};

/* Find the nearest hangar to v
 * INVALID_STATION is returned, if the player does not have any suitable
 * airports (like helipads only)
 */
static StationID FindNearestHangar(const Vehicle *v)
{
	const Station *st;
	uint best = 0;
	StationID index = INVALID_STATION;

	FOR_ALL_STATIONS(st) {
		if (st->owner == v->owner && st->facilities & FACIL_AIRPORT &&
				GetAirport(st->airport_type)->nof_depots > 0) {
			uint distance;

			// don't crash the plane if we know it can't land at the airport
			if (HASBIT(v->subtype, 1) && st->airport_type == AT_SMALL &&
					!_cheats.no_jetcrash.value)
				continue;

			distance = DistanceSquare(v->tile, st->airport_tile);
			if (distance < best || index == INVALID_STATION) {
				best = distance;
				index = st->index;
			}
		}
	}
	return index;
}

#if 0
// returns true if vehicle v have an airport in the schedule, that has a hangar
static bool HaveHangarInOrderList(Vehicle *v)
{
	const Order *order;

	FOR_VEHICLE_ORDERS(v, order) {
		const Station *st = GetStation(order->station);
		if (st->owner == v->owner && st->facilities & FACIL_AIRPORT) {
			// If an airport doesn't have terminals (so no landing space for airports),
			// it surely doesn't have any hangars
			if (GetAirport(st->airport_type)->terminals != NULL)
				return true;
		}
	}

	return false;
}
#endif

int GetAircraftImage(const Vehicle *v, byte direction)
{
	int spritenum = v->spritenum;

	if (is_custom_sprite(spritenum)) {
		int sprite = GetCustomVehicleSprite(v, direction);

		if (sprite) return sprite;
		spritenum = orig_aircraft_vehicle_info[v->engine_type - AIRCRAFT_ENGINES_INDEX].image_index;
	}
	return direction + _aircraft_sprite[spritenum];
}

void DrawAircraftEngine(int x, int y, EngineID engine, uint32 image_ormod)
{
	int spritenum = AircraftVehInfo(engine)->image_index;
	int sprite = (6 + _aircraft_sprite[spritenum]);

	if (is_custom_sprite(spritenum)) {
		sprite = GetCustomVehicleIcon(engine, 6);
		if (!sprite)
			spritenum = orig_aircraft_vehicle_info[engine - AIRCRAFT_ENGINES_INDEX].image_index;
	}

	DrawSprite(sprite | image_ormod, x, y);

	if ((AircraftVehInfo(engine)->subtype & 1) == 0) {
		DrawSprite(SPR_ROTOR_STOPPED, x, y - 5);
	}
}

/* Allocate many vehicles */
static bool AllocateVehicles(Vehicle **vl, int num)
{
	int i;
	Vehicle *v;
	bool success = true;

	for(i=0; i!=num; i++) {
		vl[i] = v = AllocateVehicle();
		if (v == NULL) {
			success = false;
			break;
		}
		v->type = 1;
	}

	while (--i >= 0) {
		vl[i]->type = 0;
	}

	return success;
}

int32 EstimateAircraftCost(EngineID engine_type)
{
	return AircraftVehInfo(engine_type)->base_cost * (_price.aircraft_base>>3)>>5;
}


/** Build an aircraft.
 * @param x,y tile coordinates of depot where aircraft is built
 * @param p1 aircraft type being built (engine)
 * @param p2 unused
 */
int32 CmdBuildAircraft(int x, int y, uint32 flags, uint32 p1, uint32 p2)
{
	int32 value;
	Vehicle *vl[3], *v, *u, *w;
	UnitID unit_num;
	TileIndex tile = TileVirtXY(x, y);
	const AircraftVehicleInfo *avi;
	Engine *e;

	if (!IsEngineBuildable(p1, VEH_Aircraft)) return CMD_ERROR;

	value = EstimateAircraftCost(p1);

	// to just query the cost, it is not neccessary to have a valid tile (automation/AI)
	if (flags & DC_QUERY_COST) return value;

	if (!IsAircraftHangarTile(tile) || !IsTileOwner(tile, _current_player)) return CMD_ERROR;

	SET_EXPENSES_TYPE(EXPENSES_NEW_VEHICLES);

	avi = AircraftVehInfo(p1);
	// allocate 2 or 3 vehicle structs, depending on type
	if (!AllocateVehicles(vl, (avi->subtype & 1) == 0 ? 3 : 2) ||
				IsOrderPoolFull())
					return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);

	unit_num = GetFreeUnitNumber(VEH_Aircraft);
	if (unit_num > _patches.max_aircraft)
		return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);

	if (flags & DC_EXEC) {
		v = vl[0];
		u = vl[1];

		v->unitnumber = unit_num;
		v->type = u->type = VEH_Aircraft;
		v->direction = 3;

		v->owner = u->owner = _current_player;

		v->tile = tile;
//		u->tile = 0;

		x = TileX(tile) * 16 + 5;
		y = TileY(tile) * 16 + 3;

		v->x_pos = u->x_pos = x;
		v->y_pos = u->y_pos = y;

		u->z_pos = GetSlopeZ(x, y);
		v->z_pos = u->z_pos + 1;

		v->x_offs = v->y_offs = -1;
//		u->delta_x = u->delta_y = 0;

		v->sprite_width = v->sprite_height = 2;
		v->z_height = 5;

		u->sprite_width = u->sprite_height = 2;
		u->z_height = 1;

		v->vehstatus = VS_HIDDEN | VS_STOPPED | VS_DEFPAL;
		u->vehstatus = VS_HIDDEN | VS_UNCLICKABLE | VS_DISASTER;

		v->spritenum = avi->image_index;
//		v->cargo_count = u->number_of_pieces = 0;

		v->cargo_cap = avi->passenger_capacity;
		u->cargo_cap = avi->mail_capacity;

		v->cargo_type = CT_PASSENGERS;
		u->cargo_type = CT_MAIL;

		v->string_id = STR_SV_AIRCRAFT_NAME;
//		v->next_order_param = v->next_order = 0;

//		v->load_unload_time_rem = 0;
//		v->progress = 0;
		v->last_station_visited = INVALID_STATION;
//		v->destination_coords = 0;

		v->max_speed = avi->max_speed;
		v->acceleration = avi->acceleration;
		v->engine_type = p1;

		v->subtype = (avi->subtype & 1) == 0 ? 0 : 2;
		v->value = value;

		u->subtype = 4;

		e = GetEngine(p1);
		v->reliability = e->reliability;
		v->reliability_spd_dec = e->reliability_spd_dec;
		v->max_age = e->lifelength * 366;

		_new_aircraft_id = v->index;

		v->u.air.pos = MAX_ELEMENTS;

		/* When we click on hangar we know the tile it is on. By that we know
		 * its position in the array of depots the airport has.....we can search
		 * layout for #th position of depot. Since layout must start with a listing
		 * of all depots, it is simple */
		{
			const Station* st = GetStation(_m[tile].m2);
			const AirportFTAClass* apc = GetAirport(st->airport_type);
			uint i;

			for (i = 0; i < apc->nof_depots; i++) {
				if (st->airport_tile + ToTileIndexDiff(apc->airport_depots[i]) == tile) {
					assert(apc->layout[i].heading == HANGAR);
					v->u.air.pos = apc->layout[i].position;
					break;
				}
			}
			// to ensure v->u.air.pos has been given a value
			assert(v->u.air.pos != MAX_ELEMENTS);
		}

		v->u.air.state = HANGAR;
		v->u.air.previous_pos = v->u.air.pos;
		v->u.air.targetairport = _m[tile].m2;
		v->next = u;

		v->service_interval = _patches.servint_aircraft;

		v->date_of_last_service = _date;
		v->build_year = u->build_year = _cur_year;

		v->cur_image = u->cur_image = 0xEA0;

		VehiclePositionChanged(v);
		VehiclePositionChanged(u);

		// Aircraft with 3 vehicles (chopper)?
		if (v->subtype == 0) {
			w = vl[2];

			u->next = w;

			w->type = VEH_Aircraft;
			w->direction = 0;
			w->owner = _current_player;
			w->x_pos = v->x_pos;
			w->y_pos = v->y_pos;
			w->z_pos = v->z_pos + 5;
			w->x_offs = w->y_offs = -1;
			w->sprite_width = w->sprite_height = 2;
			w->z_height = 1;
			w->vehstatus = VS_HIDDEN | VS_UNCLICKABLE;
			w->subtype = 6;
			w->cur_image = SPR_ROTOR_STOPPED;
			VehiclePositionChanged(w);
		}

		InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);
		RebuildVehicleLists();
		InvalidateWindow(WC_COMPANY, v->owner);
		InvalidateWindow(WC_REPLACE_VEHICLE, VEH_Aircraft); //updates the replace Aircraft window
	}

	return value;
}

bool IsAircraftHangarTile(TileIndex tile)
{
	// 0x56 - hangar facing other way international airport (86)
	// 0x20 - hangar large airport (32)
	// 0x41 - hangar small airport (65)
	return IsTileType(tile, MP_STATION) &&
				(_m[tile].m5 == 32 || _m[tile].m5 == 65 || _m[tile].m5 == 86);
}

bool CheckStoppedInHangar(Vehicle *v)
{
	if (!(v->vehstatus & VS_STOPPED) || !IsAircraftHangarTile(v->tile)) {
		_error_message = STR_A01B_AIRCRAFT_MUST_BE_STOPPED;
		return false;
	}

	return true;
}


static void DoDeleteAircraft(Vehicle *v)
{
	DeleteWindowById(WC_VEHICLE_VIEW, v->index);
	RebuildVehicleLists();
	InvalidateWindow(WC_COMPANY, v->owner);
	DeleteVehicleChain(v);
	InvalidateWindowClasses(WC_AIRCRAFT_LIST);
}

/** Sell an aircraft.
 * @param x,y unused
 * @param p1 vehicle ID to be sold
 * @param p2 unused
 */
int32 CmdSellAircraft(int x, int y, uint32 flags, uint32 p1, uint32 p2)
{
	Vehicle *v;

	if (!IsVehicleIndex(p1)) return CMD_ERROR;

	v = GetVehicle(p1);

	if (v->type != VEH_Aircraft || !CheckOwnership(v->owner) || !CheckStoppedInHangar(v))
		return CMD_ERROR;

	SET_EXPENSES_TYPE(EXPENSES_NEW_VEHICLES);

	if (flags & DC_EXEC) {
		// Invalidate depot
		InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);
		DoDeleteAircraft(v);
		InvalidateWindow(WC_REPLACE_VEHICLE, VEH_Aircraft); // updates the replace Aircraft window
	}

	return -(int32)v->value;
}

/** Start/Stop an aircraft.
 * @param x,y unused
 * @param p1 aircraft ID to start/stop
 * @param p2 unused
 */
int32 CmdStartStopAircraft(int x, int y, uint32 flags, uint32 p1, uint32 p2)
{
	Vehicle *v;

	if (!IsVehicleIndex(p1)) return CMD_ERROR;

	v = GetVehicle(p1);

	if (v->type != VEH_Aircraft || !CheckOwnership(v->owner)) return CMD_ERROR;

	// cannot stop airplane when in flight, or when taking off / landing
	if (v->u.air.state >= STARTTAKEOFF)
		return_cmd_error(STR_A017_AIRCRAFT_IS_IN_FLIGHT);

	if (flags & DC_EXEC) {
		v->vehstatus ^= VS_STOPPED;
		InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, STATUS_BAR);
		InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);
		InvalidateWindowClasses(WC_AIRCRAFT_LIST);
	}

	return 0;
}

/** Send an aircraft to the hangar.
 * @param x,y unused
 * @param p1 vehicle ID to send to the hangar
 * @param p2 various bitmasked elements
 * - p2 = 0      - aircraft goes to the depot and stays there (user command)
 * - p2 non-zero - aircraft will try to goto a depot, but not stop there (eg forced servicing)
 * - p2 (bit 17) - aircraft will try to goto a depot at the next airport
 */
int32 CmdSendAircraftToHangar(int x, int y, uint32 flags, uint32 p1, uint32 p2)
{
	Vehicle *v;

	if (!IsVehicleIndex(p1)) return CMD_ERROR;

	v = GetVehicle(p1);

	if (v->type != VEH_Aircraft || !CheckOwnership(v->owner)) return CMD_ERROR;

	if (v->current_order.type == OT_GOTO_DEPOT && p2 == 0) {
		if (flags & DC_EXEC) {
			if (v->current_order.flags & OF_UNLOAD) v->cur_order_index++;
			v->current_order.type = OT_DUMMY;
			v->current_order.flags = 0;
			InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, STATUS_BAR);
		}
	} else {
		bool next_airport_has_hangar = true;
		/* XXX - I don't think p2 is any valid station cause all calls use either 0, 1, or 1<<16!!!!!!!!! */
		StationID next_airport_index = (HASBIT(p2, 17)) ? (StationID)p2 : v->u.air.targetairport;
		const Station *st = GetStation(next_airport_index);
		// If an airport doesn't have terminals (so no landing space for airports),
		// it surely doesn't have any hangars
		if (!IsValidStation(st) || st->airport_tile == 0 || GetAirport(st->airport_type)->nof_depots == 0) {
			StationID station;

			if (p2 != 0) return CMD_ERROR;
			// the aircraft has to search for a hangar on its own
			station = FindNearestHangar(v);

			next_airport_has_hangar = false;
			if (station == INVALID_STATION) return CMD_ERROR;
			st = GetStation(station);
			next_airport_index = station;

		}

		if (flags & DC_EXEC) {
			v->current_order.type = OT_GOTO_DEPOT;
			v->current_order.flags = HASBIT(p2, 16) ? 0 : OF_NON_STOP | OF_FULL_LOAD;
			v->current_order.station = next_airport_index;
			InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, STATUS_BAR);
			if (HASBIT(p2, 17) || (p2 == 0 && v->u.air.state == FLYING && !next_airport_has_hangar)) {
			// the aircraft is now heading for a different hangar than the next in the orders
				AircraftNextAirportPos_and_Order(v);
				v->u.air.targetairport = next_airport_index;
			}
		}
	}

	return 0;
}

/** Change the service interval for aircraft.
 * @param x,y unused
 * @param p1 vehicle ID that is being service-interval-changed
 * @param p2 new service interval
 */
int32 CmdChangeAircraftServiceInt(int x, int y, uint32 flags, uint32 p1, uint32 p2)
{
	Vehicle *v;
	uint16 serv_int = GetServiceIntervalClamped(p2); /* Double check the service interval from the user-input */

	if (serv_int != p2 || !IsVehicleIndex(p1)) return CMD_ERROR;

	v = GetVehicle(p1);

	if (v->type != VEH_Aircraft || !CheckOwnership(v->owner)) return CMD_ERROR;

	if (flags & DC_EXEC) {
		v->service_interval = serv_int;
		InvalidateWindowWidget(WC_VEHICLE_DETAILS, v->index, 7);
	}

	return 0;
}

/** Refits an aircraft to the specified cargo type.
 * @param x,y unused
 * @param p1 vehicle ID of the aircraft to refit
 * @param p2 various bitstuffed elements
 * - p2 = (bit 0-7) - the new cargo type to refit to (p2 & 0xFF)
 * - p2 = (bit 8)   - skip check for stopped in hangar, used by autoreplace (p2 & 0x100)
 * @todo p2 bit8 check <b>NEEDS TO GO</b>
 */
int32 CmdRefitAircraft(int x, int y, uint32 flags, uint32 p1, uint32 p2)
{
	Vehicle *v;
	int pass, mail;
	int32 cost;
	bool SkipStoppedInHangerCheck = !!HASBIT(p2, 8); // XXX - needs to go, yes?
	CargoID new_cid = p2 & 0xFF; //gets the cargo number
	const AircraftVehicleInfo *avi;

	if (!IsVehicleIndex(p1)) return CMD_ERROR;

	v = GetVehicle(p1);

	if (v->type != VEH_Aircraft || !CheckOwnership(v->owner)) return CMD_ERROR;
	if (!SkipStoppedInHangerCheck && !CheckStoppedInHangar(v)) return_cmd_error(STR_A01B_AIRCRAFT_MUST_BE_STOPPED);

	avi = AircraftVehInfo(v->engine_type);

	/* Check cargo */
	if (new_cid > NUM_CARGO || !CanRefitTo(v, new_cid)) return CMD_ERROR;

	SET_EXPENSES_TYPE(EXPENSES_AIRCRAFT_RUN);

	switch (new_cid) {
		case CT_PASSENGERS:
			pass = avi->passenger_capacity;
			break;
		case CT_MAIL:
			pass = avi->passenger_capacity + avi->mail_capacity;
			break;
		case CT_GOODS:
			pass = avi->passenger_capacity + avi->mail_capacity;
			pass /= 2;
			break;
		default:
			pass = avi->passenger_capacity + avi->mail_capacity;
			pass /= 4;
			break;
	}
	_aircraft_refit_capacity = pass;

	cost = 0;
	if (IS_HUMAN_PLAYER(v->owner) && new_cid != v->cargo_type) {
		cost = _price.aircraft_base >> 7;
	}

	if (flags & DC_EXEC) {
		Vehicle *u;
		v->cargo_cap = pass;

		u = v->next;
		mail = (new_cid != CT_PASSENGERS) ? 0 : avi->mail_capacity;
		u->cargo_cap = mail;
		//autorefitted planes wants to keep the cargo
		//it will be checked if the cargo is valid in CmdReplaceVehicle
		if (!(SkipStoppedInHangerCheck))
			v->cargo_count = u->cargo_count = 0;
		v->cargo_type = new_cid;
		InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
	}

	return cost;
}

void HandleClickOnAircraft(Vehicle *v)
{
	ShowAircraftViewWindow(v);
}

static void CheckIfAircraftNeedsService(Vehicle *v)
{
	Station *st;

	if (_patches.servint_aircraft == 0)
		return;

	if (!VehicleNeedsService(v))
		return;

	if (v->vehstatus & VS_STOPPED)
		return;

	if (v->current_order.type == OT_GOTO_DEPOT &&
			v->current_order.flags & OF_HALT_IN_DEPOT)
		return;

	if (_patches.gotodepot && VehicleHasDepotOrders(v))
 		return;

	st = GetStation(v->current_order.station);
	// only goto depot if the target airport has terminals (eg. it is airport)
	if (st->xy != 0 && st->airport_tile != 0 && GetAirport(st->airport_type)->terminals != NULL) {
//		printf("targetairport = %d, st->index = %d\n", v->u.air.targetairport, st->index);
//		v->u.air.targetairport = st->index;
		v->current_order.type = OT_GOTO_DEPOT;
		v->current_order.flags = OF_NON_STOP;
		InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, STATUS_BAR);
	} else if (v->current_order.type == OT_GOTO_DEPOT) {
		v->current_order.type = OT_DUMMY;
		v->current_order.flags = 0;
		InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, STATUS_BAR);
	}
}

void OnNewDay_Aircraft(Vehicle *v)
{
	int32 cost;

	if (v->subtype > 2)
		return;

	if ((++v->day_counter & 7) == 0)
		DecreaseVehicleValue(v);

	CheckOrders(v->index, OC_INIT);

	CheckVehicleBreakdown(v);
	AgeVehicle(v);
	CheckIfAircraftNeedsService(v);

	if (v->vehstatus & VS_STOPPED)
		return;

	cost = AircraftVehInfo(v->engine_type)->running_cost * _price.aircraft_running / 364;

	v->profit_this_year -= cost >> 8;

	SET_EXPENSES_TYPE(EXPENSES_AIRCRAFT_RUN);
	SubtractMoneyFromPlayerFract(v->owner, cost);

	InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
	InvalidateWindowClasses(WC_AIRCRAFT_LIST);
}

void AircraftYearlyLoop(void)
{
	Vehicle *v;

	FOR_ALL_VEHICLES(v) {
		if (v->type == VEH_Aircraft && v->subtype <= 2) {
			v->profit_last_year = v->profit_this_year;
			v->profit_this_year = 0;
			InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
		}
	}
}

static void AgeAircraftCargo(Vehicle *v)
{
	if (_age_cargo_skip_counter != 0)
		return;

	do {
		if (v->cargo_days != 0xFF)
			v->cargo_days++;
	} while ( (v=v->next) != NULL );
}

static void HelicopterTickHandler(Vehicle *v)
{
	Vehicle *u;
	int tick,spd;
	uint16 img;

	u = v->next->next;

	if (u->vehstatus & VS_HIDDEN)
		return;

	// if true, helicopter rotors do not rotate. This should only be the case if a helicopter is
	// loading/unloading at a terminal or stopped
	if (v->current_order.type == OT_LOADING || (v->vehstatus & VS_STOPPED)) {
		if (u->cur_speed != 0) {
			u->cur_speed++;
			if (u->cur_speed >= 0x80 && u->cur_image == SPR_ROTOR_MOVING_3) {
				u->cur_speed = 0;
			}
		}
	} else {
		if (u->cur_speed == 0)
			u->cur_speed = 0x70;

		if (u->cur_speed >= 0x50)
			u->cur_speed--;
	}

	tick = ++u->tick_counter;
	spd = u->cur_speed >> 4;

	if (spd == 0) {
		img = SPR_ROTOR_STOPPED;
		if (u->cur_image == img)
			return;
	} else if (tick >= spd) {
		u->tick_counter = 0;
		img = u->cur_image + 1;
		if (img > SPR_ROTOR_MOVING_3) img = SPR_ROTOR_MOVING_1;
	} else
		return;

	u->cur_image=img;

	BeginVehicleMove(u);
	VehiclePositionChanged(u);
	EndVehicleMove(u);
}

static void SetAircraftPosition(Vehicle *v, int x, int y, int z)
{
	Vehicle *u;
	int yt;

	v->x_pos = x;
	v->y_pos = y;
	v->z_pos = z;

	v->cur_image = GetAircraftImage(v, v->direction);

	BeginVehicleMove(v);
	VehiclePositionChanged(v);
	EndVehicleMove(v);

	u = v->next;

	yt = y - ((v->z_pos-GetSlopeZ(x, y-1)) >> 3);
	u->x_pos = x;
	u->y_pos = yt;
	u->z_pos = GetSlopeZ(x,yt);
	u->cur_image = v->cur_image;

	BeginVehicleMove(u);
	VehiclePositionChanged(u);
	EndVehicleMove(u);

	if ((u=u->next) != NULL) {
		u->x_pos = x;
		u->y_pos = y;
		u->z_pos = z + 5;

		BeginVehicleMove(u);
		VehiclePositionChanged(u);
		EndVehicleMove(u);
	}
}

static void ServiceAircraft(Vehicle *v)
{
	Vehicle *u;

	v->cur_speed = 0;
	v->subspeed = 0;
	v->progress = 0;
	v->vehstatus |= VS_HIDDEN;

	u = v->next;
	u->vehstatus |= VS_HIDDEN;
	if ((u=u->next) != NULL) {
		u->vehstatus |= VS_HIDDEN;
		u->cur_speed = 0;
	}

	SetAircraftPosition(v, v->x_pos, v->y_pos, v->z_pos);
	InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);

	VehicleServiceInDepot(v);
	InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
}

static void PlayAircraftSound(Vehicle *v)
{
	SndPlayVehicleFx(AircraftVehInfo(v->engine_type)->sfx, v);
}

static bool UpdateAircraftSpeed(Vehicle *v)
{
	uint spd = v->acceleration * 2;
	byte t;

	v->subspeed = (t=v->subspeed) + (byte)spd;
	spd = min( v->cur_speed + (spd >> 8) + (v->subspeed < t), v->max_speed);

	// adjust speed for broken vehicles
	if(v->vehstatus&VS_AIRCRAFT_BROKEN) spd = min(spd, 27);

	//updates statusbar only if speed have changed to save CPU time
	if (spd != v->cur_speed) {
		v->cur_speed = spd;
		if (_patches.vehicle_speed)
			InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, STATUS_BAR);
	}

	if (!(v->direction & 1)) {
		spd = spd * 3 >> 2;
	}

	if (spd == 0)
		return false;

	if ((byte)++spd == 0)
		return true;

	v->progress = (t = v->progress) - (byte)spd;

	return (t < v->progress);
}

// get Aircraft running altitude
static byte GetAircraftFlyingAltitude(const Vehicle *v)
{
	switch (v->max_speed) {
		case 37: return 162;
		case 74: return 171;
		default: return 180;
	}
}

static bool AircraftController(Vehicle *v)
{
	Station *st;
	const AirportMovingData *amd;
	Vehicle *u;
	byte z,dirdiff,newdir,maxz,curz;
	GetNewVehiclePosResult gp;
	uint dist;
	int x,y;

	st = GetStation(v->u.air.targetairport);

	// prevent going to 0,0 if airport is deleted.
	{
		TileIndex tile = st->airport_tile;

		if (tile == 0) tile = st->xy;
		// xy of destination
		x = TileX(tile) * 16;
		y = TileY(tile) * 16;
	}

	// get airport moving data
	assert(v->u.air.pos < GetAirport(st->airport_type)->nofelements);
	amd = &_airport_moving_datas[st->airport_type][v->u.air.pos];

	// Helicopter raise
	if (amd->flag & AMED_HELI_RAISE) {
		u = v->next->next;

		// Make sure the rotors don't rotate too fast
		if (u->cur_speed > 32) {
			v->cur_speed = 0;
			if (--u->cur_speed == 32) {
				SndPlayVehicleFx(SND_18_HELICOPTER, v);
			}
		} else {
			u->cur_speed = 32;
			if (UpdateAircraftSpeed(v)) {
				v->tile = 0;

				// Reached altitude?
				if (v->z_pos >= 184) {
					v->cur_speed = 0;
					return true;
				}
				SetAircraftPosition(v, v->x_pos, v->y_pos, v->z_pos+1);
			}
		}
		return false;
	}

	// Helicopter landing.
	if (amd->flag & AMED_HELI_LOWER) {
		if (UpdateAircraftSpeed(v)) {
			if (st->airport_tile == 0) {
				// FIXME - AircraftController -> if station no longer exists, do not land
				// helicopter will circle until sign disappears, then go to next order
				// * what to do when it is the only order left, right now it just stays in 1 place
				v->u.air.state = FLYING;
				AircraftNextAirportPos_and_Order(v);
				return false;
			}

			// Vehicle is now at the airport.
			v->tile = st->airport_tile;

			// Find altitude of landing position.
			z = GetSlopeZ(x, y) + 1;
			if (st->airport_type == AT_OILRIG) z += 54;
			if (st->airport_type == AT_HELIPORT) z += 60;

			if (z == v->z_pos) {
				u = v->next->next;

				// Increase speed of rotors. When speed is 80, we've landed.
				if (u->cur_speed >= 80)
					return true;
				u->cur_speed+=4;
			} else if (v->z_pos > z) {
				SetAircraftPosition(v, v->x_pos, v->y_pos, v->z_pos-1);
			} else {
				SetAircraftPosition(v, v->x_pos, v->y_pos, v->z_pos+1);
			}
		}
		return false;
	}

	// Get distance from destination pos to current pos.
	dist = myabs(x + amd->x - v->x_pos) +  myabs(y + amd->y - v->y_pos);

	// Need exact position?
	if (!(amd->flag & AMED_EXACTPOS) && dist <= (amd->flag & AMED_SLOWTURN ? 8U : 4U))
		return true;

	// At final pos?
	if (dist == 0) {

		// Clamp speed to 12.
		if (v->cur_speed > 12)
			v->cur_speed = 12;

		// Change direction smoothly to final direction.
		dirdiff = amd->direction - v->direction;
		// if distance is 0, and plane points in right direction, no point in calling
		// UpdateAircraftSpeed(). So do it only afterwards
		if (dirdiff == 0) {
			v->cur_speed = 0;
			return true;
		}

		if (!UpdateAircraftSpeed(v))
			return false;

		v->direction = (v->direction+((dirdiff&7)<5?1:-1)) & 7;
		v->cur_speed >>= 1;

		SetAircraftPosition(v, v->x_pos, v->y_pos, v->z_pos);
		return false;
	}

	// Clamp speed?
	if (!(amd->flag & AMED_NOSPDCLAMP) && v->cur_speed > 12)
		v->cur_speed = 12;

	if (!UpdateAircraftSpeed(v))
		return false;

	// Decrease animation counter.
	if (v->load_unload_time_rem != 0)
		v->load_unload_time_rem--;

	// Turn. Do it slowly if in the air.
	newdir = GetDirectionTowards(v, x + amd->x, y + amd->y);
	if (newdir != v->direction) {
		if (amd->flag & AMED_SLOWTURN) {
			if (v->load_unload_time_rem == 0) {
				v->load_unload_time_rem = 8;
			}
			v->direction = newdir;
		} else {
			v->cur_speed >>= 1;
			v->direction = newdir;
		}
	}

	// Move vehicle.
	GetNewVehiclePos(v, &gp);
	v->tile = gp.new_tile;

	// If vehicle is in the air, use tile coordinate 0.
	if (amd->flag & (AMED_TAKEOFF | AMED_SLOWTURN | AMED_LAND)) {
		v->tile = 0;
	}

	// Adjust Z for land or takeoff?
	z = v->z_pos;

	if (amd->flag & AMED_TAKEOFF) {
		z+=2;
		// Determine running altitude
		maxz = GetAircraftFlyingAltitude(v);
		if (z > maxz)
			z = maxz;
	}

	if (amd->flag & AMED_LAND) {
		if (st->airport_tile == 0) {
			v->u.air.state = FLYING;
			AircraftNextAirportPos_and_Order(v);
			// get aircraft back on running altitude
			SetAircraftPosition(v, gp.x, gp.y, GetAircraftFlyingAltitude(v));
			return false;
		}

		curz = GetSlopeZ(x, y) + 1;

		if (curz > z) {
			z++;
		} else {
			int t = max(1, dist-4);

			z -= ((z - curz) + t - 1) / t;
			if (z < curz) z = curz;
		}
	}

	// We've landed. Decrase speed when we're reaching end of runway.
	if (amd->flag & AMED_BRAKE) {
		curz = GetSlopeZ(x, y) + 1;

		if (z > curz) z--;
		else if (z < curz) z++;

		if (dist < 64 && v->cur_speed > 12)
			v->cur_speed -= 4;
	}

	SetAircraftPosition(v, gp.x, gp.y, z);
	return false;
}

static const int8 _crashed_aircraft_moddir[4] = {
	-1,0,0,1
};

static void HandleCrashedAircraft(Vehicle *v)
{
	uint32 r;
	Station *st;
	int z;

	v->u.air.crashed_counter++;

	st = GetStation(v->u.air.targetairport);

	// make aircraft crash down to the ground
	if (v->u.air.crashed_counter < 500 && st->airport_tile==0 && ((v->u.air.crashed_counter % 3) == 0) ) {
		z = GetSlopeZ(v->x_pos, v->y_pos);
		v->z_pos -= 1;
		if (v->z_pos == z) {
			v->u.air.crashed_counter = 500;
			v->z_pos++;
		}
	}

	if (v->u.air.crashed_counter < 650) {
		if (CHANCE16R(1,32,r)) {
			v->direction = (v->direction + _crashed_aircraft_moddir[GB(r, 16, 2)]) & 7;
			SetAircraftPosition(v, v->x_pos, v->y_pos, v->z_pos);
			r = Random();
			CreateEffectVehicleRel(v,
				GB(r, 0, 4) + 4,
				GB(r, 4, 4) + 4,
				GB(r, 8, 4),
				EV_EXPLOSION_SMALL);
		}
	} else if (v->u.air.crashed_counter >= 10000) {
		// remove rubble of crashed airplane

		// clear runway-in on all airports, set by crashing plane
		// small airports use AIRPORT_BUSY, city airports use RUNWAY_IN_OUT_block, etc.
		// but they all share the same number
		CLRBITS(st->airport_flags, RUNWAY_IN_block);

		BeginVehicleMove(v);
		EndVehicleMove(v);

		DoDeleteAircraft(v);
	}
}

static void HandleBrokenAircraft(Vehicle *v)
{
	if (v->breakdown_ctr != 1) {
		v->breakdown_ctr = 1;
		v->vehstatus |= VS_AIRCRAFT_BROKEN;

		if (v->breakdowns_since_last_service != 255)
			v->breakdowns_since_last_service++;
		InvalidateWindow(WC_VEHICLE_VIEW, v->index);
		InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
	}
}

static const int8 _aircraft_smoke_xy[16] = {
	5,6,5,0,-5,-6,-5,0, /* x coordinates */
	5,0,-5,-6,-5,0,5,6, /* y coordinate */
};

static void HandleAircraftSmoke(Vehicle *v)
{
	if (!(v->vehstatus&VS_AIRCRAFT_BROKEN))
		return;

	if (v->cur_speed < 10) {
		v->vehstatus &= ~VS_AIRCRAFT_BROKEN;
		v->breakdown_ctr = 0;
		return;
	}

	if ((v->tick_counter & 0x1F) == 0) {
		CreateEffectVehicleRel(v,
			_aircraft_smoke_xy[v->direction],
			_aircraft_smoke_xy[v->direction + 8],
			2,
			EV_SMOKE
		);
	}
}

static void ProcessAircraftOrder(Vehicle *v)
{
	const Order *order;

	// OT_GOTO_DEPOT, OT_LOADING
	if (v->current_order.type == OT_GOTO_DEPOT ||
			v->current_order.type == OT_LOADING) {
		if (v->current_order.type != OT_GOTO_DEPOT ||
				!(v->current_order.flags & OF_UNLOAD))
			return;
	}

	if (v->current_order.type == OT_GOTO_DEPOT &&
			(v->current_order.flags & (OF_PART_OF_ORDERS | OF_SERVICE_IF_NEEDED)) == (OF_PART_OF_ORDERS | OF_SERVICE_IF_NEEDED) &&
 			!VehicleNeedsService(v)) {
			v->cur_order_index++;
		}

	if (v->cur_order_index >= v->num_orders)
		v->cur_order_index = 0;

	order = GetVehicleOrder(v, v->cur_order_index);

	if (order == NULL) {
		v->current_order.type = OT_NOTHING;
		v->current_order.flags = 0;
		return;
	}

	if (order->type == OT_DUMMY && !CheckForValidOrders(v))
		CrashAirplane(v);

	if (order->type    == v->current_order.type   &&
			order->flags   == v->current_order.flags  &&
			order->station == v->current_order.station)
		return;

	v->current_order = *order;

	// orders are changed in flight, ensure going to the right station
	if (order->type == OT_GOTO_STATION && v->u.air.state == FLYING) {
		AircraftNextAirportPos_and_Order(v);
		v->u.air.targetairport = order->station;
	}

	InvalidateVehicleOrder(v);

	InvalidateWindowClasses(WC_AIRCRAFT_LIST);
}

static void HandleAircraftLoading(Vehicle *v, int mode)
{
	if (v->current_order.type == OT_NOTHING)
		return;

	if (v->current_order.type != OT_DUMMY) {
		if (v->current_order.type != OT_LOADING)
			return;

		if (mode != 0)
			return;

		if (--v->load_unload_time_rem)
			return;

		if (v->current_order.flags & OF_FULL_LOAD && CanFillVehicle(v)) {
			SET_EXPENSES_TYPE(EXPENSES_AIRCRAFT_INC);
			LoadUnloadVehicle(v);
			return;
		}

		{
			Order b = v->current_order;
			v->current_order.type = OT_NOTHING;
			v->current_order.flags = 0;
			if (!(b.flags & OF_NON_STOP))
				return;
		}
	}
	v->cur_order_index++;
	InvalidateVehicleOrder(v);
}

static void CrashAirplane(Vehicle *v)
{
	uint16 amt;
	Station *st;
	StringID newsitem;

	v->vehstatus |= VS_CRASHED;
	v->u.air.crashed_counter = 0;

	CreateEffectVehicleRel(v, 4, 4, 8, EV_EXPLOSION_LARGE);

	InvalidateWindow(WC_VEHICLE_VIEW, v->index);

	amt = 2;
	if (v->cargo_type == CT_PASSENGERS) amt += v->cargo_count;
	SetDParam(0, amt);

	v->cargo_count = 0;
	v->next->cargo_count = 0,
	st = GetStation(v->u.air.targetairport);
	if(st->airport_tile==0) {
		newsitem = STR_PLANE_CRASH_OUT_OF_FUEL;
	} else {
		SetDParam(1, st->index);
		newsitem = STR_A034_PLANE_CRASH_DIE_IN_FIREBALL;
	}

	SetDParam(1, st->index);
	AddNewsItem(newsitem,
		NEWS_FLAGS(NM_THIN, NF_VIEWPORT|NF_VEHICLE, NT_ACCIDENT, 0),
		v->index,
		0);

	SndPlayVehicleFx(SND_12_EXPLOSION, v);
}

static void MaybeCrashAirplane(Vehicle *v)
{
	Station *st;
	uint16 prob;
	int i;

	st = GetStation(v->u.air.targetairport);

	//FIXME -- MaybeCrashAirplane -> increase crashing chances of very modern airplanes on smaller than AT_METROPOLITAN airports
	prob = 0x10000 / 1500;
	if (st->airport_type == AT_SMALL && (AircraftVehInfo(v->engine_type)->subtype & 2) && !_cheats.no_jetcrash.value) {
		prob = 0x10000 / 20;
	}

	if (GB(Random(), 0, 16) > prob) return;

	// Crash the airplane. Remove all goods stored at the station.
	for(i=0; i!=NUM_CARGO; i++) {
		st->goods[i].rating = 1;
		SB(st->goods[i].waiting_acceptance, 0, 12, 0);
	}

	CrashAirplane(v);
}

// we've landed and just arrived at a terminal
static void AircraftEntersTerminal(Vehicle *v)
{
	Station *st;
	Order old_order;

	if (v->current_order.type == OT_GOTO_DEPOT)
		return;

	st = GetStation(v->u.air.targetairport);
	v->last_station_visited = v->u.air.targetairport;

	/* Check if station was ever visited before */
	if (!(st->had_vehicle_of_type & HVOT_AIRCRAFT)) {
		uint32 flags;

		st->had_vehicle_of_type |= HVOT_AIRCRAFT;
		SetDParam(0, st->index);
		// show newsitem of celebrating citizens
		flags = (v->owner == _local_player) ? NEWS_FLAGS(NM_THIN, NF_VIEWPORT|NF_VEHICLE, NT_ARRIVAL_PLAYER, 0) : NEWS_FLAGS(NM_THIN, NF_VIEWPORT|NF_VEHICLE, NT_ARRIVAL_OTHER, 0);
		AddNewsItem(
			STR_A033_CITIZENS_CELEBRATE_FIRST,
			flags,
			v->index,
			0);
	}

	old_order = v->current_order;
	v->current_order.type = OT_LOADING;
	v->current_order.flags = 0;

	if (old_order.type == OT_GOTO_STATION &&
			v->current_order.station == v->last_station_visited) {
		v->current_order.flags =
			(old_order.flags & (OF_FULL_LOAD | OF_UNLOAD)) | OF_NON_STOP;
	}

	SET_EXPENSES_TYPE(EXPENSES_AIRCRAFT_INC);
	LoadUnloadVehicle(v);
	InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, STATUS_BAR);
	InvalidateWindowClasses(WC_AIRCRAFT_LIST);
}

static bool ValidateAircraftInHangar( uint data_a, uint data_b )
{
	Vehicle *v = GetVehicle(data_a);

	return (IsAircraftHangarTile(v->tile) && (v->vehstatus & VS_STOPPED));
}

static void AircraftEnterHangar(Vehicle *v)
{
	Order old_order;

	ServiceAircraft(v);
	InvalidateWindowClasses(WC_AIRCRAFT_LIST);

	MaybeReplaceVehicle(v);

	TriggerVehicle(v, VEHICLE_TRIGGER_DEPOT);

	if (v->current_order.type == OT_GOTO_DEPOT) {
		InvalidateWindow(WC_VEHICLE_VIEW, v->index);

		old_order = v->current_order;
		v->current_order.type = OT_NOTHING;
		v->current_order.flags = 0;

		if (HASBIT(old_order.flags, OFB_PART_OF_ORDERS)) {
			v->cur_order_index++;
		} else if (HASBIT(old_order.flags, OFB_HALT_IN_DEPOT)) { // force depot visit
			v->vehstatus |= VS_STOPPED;
			InvalidateWindowClasses(WC_AIRCRAFT_LIST);

			if (v->owner == _local_player) {
				SetDParam(0, v->unitnumber);
				AddValidatedNewsItem(
					STR_A014_AIRCRAFT_IS_WAITING_IN,
					NEWS_FLAGS(NM_SMALL, NF_VIEWPORT|NF_VEHICLE, NT_ADVICE, 0),
					v->index,
					0,
					ValidateAircraftInHangar);
			}
		}
	}
}

static void AircraftLand(Vehicle *v)
{
	v->sprite_width = v->sprite_height = 2;
}

static void AircraftLandAirplane(Vehicle *v)
{
	AircraftLand(v);
	SndPlayVehicleFx(SND_17_SKID_PLANE, v);
	MaybeCrashAirplane(v);
}

// set the right pos when heading to other airports after takeoff
static void AircraftNextAirportPos_and_Order(Vehicle *v)
{
	Station *st;
	const AirportFTAClass *Airport;

	if (v->current_order.type == OT_GOTO_STATION ||
			v->current_order.type == OT_GOTO_DEPOT)
		v->u.air.targetairport = v->current_order.station;

	st = GetStation(v->u.air.targetairport);
	Airport = GetAirport(st->airport_type);
	v->u.air.pos = v->u.air.previous_pos = Airport->entry_point;
}

static void AircraftLeaveHangar(Vehicle *v)
{
	v->cur_speed = 0;
	v->subspeed = 0;
	v->progress = 0;
	v->direction = 3;
	v->vehstatus &= ~VS_HIDDEN;
	{
		Vehicle *u = v->next;
		u->vehstatus &= ~VS_HIDDEN;

		// Rotor blades
		if ((u=u->next) != NULL) {
			u->vehstatus &= ~VS_HIDDEN;
			u->cur_speed = 80;
		}
	}

	VehicleServiceInDepot(v);
	SetAircraftPosition(v, v->x_pos, v->y_pos, v->z_pos);
	InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);
	InvalidateWindowClasses(WC_AIRCRAFT_LIST);
}


////////////////////////////////////////////////////////////////////////////////
///////////////////   AIRCRAFT MOVEMENT SCHEME  ////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
static void AircraftEventHandler_EnterTerminal(Vehicle *v, const AirportFTAClass *Airport)
{
	AircraftEntersTerminal(v);
	v->u.air.state = Airport->layout[v->u.air.pos].heading;
}

static void AircraftEventHandler_EnterHangar(Vehicle *v, const AirportFTAClass *Airport)
{
	AircraftEnterHangar(v);
	v->u.air.state = Airport->layout[v->u.air.pos].heading;
}

// In an Airport Hangar
static void AircraftEventHandler_InHangar(Vehicle *v, const AirportFTAClass *Airport)
{
	// if we just arrived, execute EnterHangar first
	if (v->u.air.previous_pos != v->u.air.pos) {
		AircraftEventHandler_EnterHangar(v, Airport);
		return;
	}

	// if we were sent to the depot, stay there
	if (v->current_order.type == OT_GOTO_DEPOT && (v->vehstatus & VS_STOPPED)) {
		v->current_order.type = OT_NOTHING;
		v->current_order.flags = 0;
		return;
	}

	if (v->current_order.type != OT_GOTO_STATION &&
			v->current_order.type != OT_GOTO_DEPOT)
		return;

	// if the block of the next position is busy, stay put
	if (AirportHasBlock(v, &Airport->layout[v->u.air.pos], Airport)) {return;}

	// We are already at the target airport, we need to find a terminal
	if (v->current_order.station == v->u.air.targetairport) {
		// FindFreeTerminal:
		// 1. Find a free terminal, 2. Occupy it, 3. Set the vehicle's state to that terminal
		if (v->subtype != 0) {if(!AirportFindFreeTerminal(v, Airport)) {return;}} // airplane
		else {if(!AirportFindFreeHelipad(v, Airport)) {return;}} // helicopter
	}
	else { // Else prepare for launch.
		// airplane goto state takeoff, helicopter to helitakeoff
		v->u.air.state = (v->subtype != 0) ? TAKEOFF : HELITAKEOFF;
	}
	AircraftLeaveHangar(v);
	AirportMove(v, Airport);
}

// At one of the Airport's Terminals
static void AircraftEventHandler_AtTerminal(Vehicle *v, const AirportFTAClass *Airport)
{
	// if we just arrived, execute EnterTerminal first
	if (v->u.air.previous_pos != v->u.air.pos) {
		AircraftEventHandler_EnterTerminal(v, Airport);
		// on an airport with helipads, a helicopter will always land there
		// and get serviced at the same time - patch setting
		if (_patches.serviceathelipad) {
			if (v->subtype == 0 && Airport->helipads != NULL) {
				// an exerpt of ServiceAircraft, without the invisibility stuff
				v->date_of_last_service = _date;
				v->breakdowns_since_last_service = 0;
				v->reliability = GetEngine(v->engine_type)->reliability;
				InvalidateWindow(WC_VEHICLE_DETAILS, v->index);
			}
		}
		return;
	}

	if (v->current_order.type == OT_NOTHING) return;

	// if the block of the next position is busy, stay put
	if (AirportHasBlock(v, &Airport->layout[v->u.air.pos], Airport)) {
		return;
	}

	// airport-road is free. We either have to go to another airport, or to the hangar
	// ---> start moving

	switch (v->current_order.type) {
		case OT_GOTO_STATION: // ready to fly to another airport
			// airplane goto state takeoff, helicopter to helitakeoff
			v->u.air.state = (v->subtype != 0) ? TAKEOFF : HELITAKEOFF;
			break;
		case OT_GOTO_DEPOT:   // visit hangar for serivicing, sale, etc.
			if (v->current_order.station == v->u.air.targetairport)
				v->u.air.state = HANGAR;
			else
				v->u.air.state = (v->subtype != 0) ? TAKEOFF : HELITAKEOFF;
			break;
		default:  // orders have been deleted (no orders), goto depot and don't bother us
			v->current_order.type = OT_NOTHING;
			v->current_order.flags = 0;
			v->u.air.state = HANGAR;
	}
	AirportMove(v, Airport);
}

static void AircraftEventHandler_General(Vehicle *v, const AirportFTAClass *Airport)
{
	DEBUG(misc, 0) ("OK, you shouldn't be here, check your Airport Scheme!");
	assert(0);
}

static void AircraftEventHandler_TakeOff(Vehicle *v, const AirportFTAClass *Airport) {
	PlayAircraftSound(v); // play takeoffsound for airplanes
	v->u.air.state = STARTTAKEOFF;
}

static void AircraftEventHandler_StartTakeOff(Vehicle *v, const AirportFTAClass *Airport)
{
	v->sprite_width = v->sprite_height = 24; // ??? no idea what this is
	v->u.air.state = ENDTAKEOFF;
}

static void AircraftEventHandler_EndTakeOff(Vehicle *v, const AirportFTAClass *Airport)
{
	v->u.air.state = FLYING;
	// get the next position to go to, differs per airport
	AircraftNextAirportPos_and_Order(v);
}

static void AircraftEventHandler_HeliTakeOff(Vehicle *v, const AirportFTAClass *Airport)
{
	const Player* p = GetPlayer(v->owner);
	v->sprite_width = v->sprite_height = 24; // ??? no idea what this is
	v->u.air.state = FLYING;
	// get the next position to go to, differs per airport
	AircraftNextAirportPos_and_Order(v);

	// check if the aircraft needs to be replaced or renewed and send it to a hangar if needed
	if ((v->owner == _local_player && p->engine_replacement[v->engine_type] != INVALID_ENGINE) ||
		(v->owner == _local_player && p->engine_renew && v->age - v->max_age > (p->engine_renew_months * 30))) {
		_current_player = _local_player;
		DoCommandP(v->tile, v->index, 1, NULL, CMD_SEND_AIRCRAFT_TO_HANGAR | CMD_SHOW_NO_ERROR);
		_current_player = OWNER_NONE;
	}
}

static void AircraftEventHandler_Flying(Vehicle *v, const AirportFTAClass *Airport)
{
	Station *st;
	byte landingtype;
	AirportFTA *current;
	uint16 tcur_speed, tsubspeed;

	st = GetStation(v->u.air.targetairport);
	// flying device is accepted at this station
	// small airport --> no helicopters (AIRCRAFT_ONLY)
	// all other airports --> all types of flying devices (ALL)
	// heliport/oilrig, etc --> no airplanes (HELICOPTERS_ONLY)
	// runway busy or not allowed to use this airstation, circle
	if (! (v->subtype == Airport->acc_planes ||
			st->airport_tile == 0 || (st->owner != OWNER_NONE && st->owner != v->owner) )) {

		// {32,FLYING,NOTHING_block,37}, {32,LANDING,N,33}, {32,HELILANDING,N,41},
		// if it is an airplane, look for LANDING, for helicopter HELILANDING
		// it is possible to choose from multiple landing runways, so loop until a free one is found
		landingtype = (v->subtype != 0) ? LANDING : HELILANDING;
		current = Airport->layout[v->u.air.pos].next_in_chain;
		while (current != NULL) {
			if (current->heading == landingtype) {
				// save speed before, since if AirportHasBlock is false, it resets them to 0
				// we don't want that for plane in air
				// hack for speed thingie
				tcur_speed = v->cur_speed;
				tsubspeed = v->subspeed;
				if (!AirportHasBlock(v, current, Airport)) {
					v->u.air.state = landingtype; // LANDING / HELILANDING
					// it's a bit dirty, but I need to set position to next position, otherwise
					// if there are multiple runways, plane won't know which one it took (because
					// they all have heading LANDING). And also occupy that block!
					v->u.air.pos = current->next_position;
					SETBITS(st->airport_flags, Airport->layout[v->u.air.pos].block);
					return;
				}
				v->cur_speed = tcur_speed;
				v->subspeed = tsubspeed;
			}
			current = current->next_in_chain;
		}
	}
	v->u.air.state = FLYING;
	v->u.air.pos = Airport->layout[v->u.air.pos].next_position;
}

static void AircraftEventHandler_Landing(Vehicle *v, const AirportFTAClass *Airport)
{
	const Player* p = GetPlayer(v->owner);
	AircraftLandAirplane(v);  // maybe crash airplane
	v->u.air.state = ENDLANDING;
	// check if the aircraft needs to be replaced or renewed and send it to a hangar if needed
	if (v->current_order.type != OT_GOTO_DEPOT && v->owner == _local_player) {
		// only the vehicle owner needs to calculate the rest (locally)
		if ((p->engine_replacement[v->engine_type] != INVALID_ENGINE) ||
			(p->engine_renew && v->age - v->max_age > (p->engine_renew_months * 30))) {
			// send the aircraft to the hangar at next airport (bit 17 set)
			_current_player = _local_player;
			DoCommandP(v->tile, v->index, 1 << 16, NULL, CMD_SEND_AIRCRAFT_TO_HANGAR | CMD_SHOW_NO_ERROR);
			_current_player = OWNER_NONE;
		}
	}
}

static void AircraftEventHandler_HeliLanding(Vehicle *v, const AirportFTAClass *Airport)
{
	AircraftLand(v); // helicopters don't crash
	v->u.air.state = HELIENDLANDING;
}

static void AircraftEventHandler_EndLanding(Vehicle *v, const AirportFTAClass *Airport)
{
	// next block busy, don't do a thing, just wait
	if(AirportHasBlock(v, &Airport->layout[v->u.air.pos], Airport)) {return;}

	// if going to terminal (OT_GOTO_STATION) choose one
	// 1. in case all terminals are busy AirportFindFreeTerminal() returns false or
	// 2. not going for terminal (but depot, no order),
	// --> get out of the way to the hangar.
	if (v->current_order.type == OT_GOTO_STATION) {
		if (AirportFindFreeTerminal(v, Airport)) {return;}
	}
	v->u.air.state = HANGAR;

}

static void AircraftEventHandler_HeliEndLanding(Vehicle *v, const AirportFTAClass *Airport)
{
	// next block busy, don't do a thing, just wait
	if(AirportHasBlock(v, &Airport->layout[v->u.air.pos], Airport)) {return;}

	// if going to helipad (OT_GOTO_STATION) choose one. If airport doesn't have helipads, choose terminal
	// 1. in case all terminals/helipads are busy (AirportFindFreeHelipad() returns false) or
	// 2. not going for terminal (but depot, no order),
	// --> get out of the way to the hangar IF there are terminals on the airport.
	// --> else TAKEOFF
	// the reason behind this is that if an airport has a terminal, it also has a hangar. Airplanes
	// must go to a hangar.
	if (v->current_order.type == OT_GOTO_STATION) {
		if (AirportFindFreeHelipad(v, Airport)) {return;}
	}
	v->u.air.state = (Airport->terminals != NULL) ? HANGAR : HELITAKEOFF;
}

typedef void AircraftStateHandler(Vehicle *v, const AirportFTAClass *Airport);
static AircraftStateHandler * const _aircraft_state_handlers[] = {
	AircraftEventHandler_General,				// TO_ALL         =  0
	AircraftEventHandler_InHangar,			// HANGAR         =  1
	AircraftEventHandler_AtTerminal,		// TERM1          =  2
	AircraftEventHandler_AtTerminal,		// TERM2          =  3
	AircraftEventHandler_AtTerminal,		// TERM3          =  4
	AircraftEventHandler_AtTerminal,		// TERM4          =  5
	AircraftEventHandler_AtTerminal,		// TERM5          =  6
	AircraftEventHandler_AtTerminal,		// TERM6          =  7
	AircraftEventHandler_AtTerminal,		// HELIPAD1       =  8
	AircraftEventHandler_AtTerminal,		// HELIPAD2       =  9
	AircraftEventHandler_TakeOff,				// TAKEOFF        = 10
	AircraftEventHandler_StartTakeOff,	// STARTTAKEOFF   = 11
	AircraftEventHandler_EndTakeOff,		// ENDTAKEOFF     = 12
	AircraftEventHandler_HeliTakeOff,		// HELITAKEOFF    = 13
	AircraftEventHandler_Flying,				// FLYING         = 14
	AircraftEventHandler_Landing,				// LANDING        = 15
	AircraftEventHandler_EndLanding,		// ENDLANDING     = 16
	AircraftEventHandler_HeliLanding,		// HELILANDING    = 17
	AircraftEventHandler_HeliEndLanding,// HELIENDLANDING = 18
};

static void AirportClearBlock(Vehicle *v, const AirportFTAClass *Airport)
{
	Station *st;
	// we have left the previous block, and entered the new one. Free the previous block
	if (Airport->layout[v->u.air.previous_pos].block != Airport->layout[v->u.air.pos].block) {
		st = GetStation(v->u.air.targetairport);
		CLRBITS(st->airport_flags, Airport->layout[v->u.air.previous_pos].block);
	}
}

static void AirportGoToNextPosition(Vehicle *v, const AirportFTAClass *Airport)
{
	// if aircraft is not in position, wait until it is
	if (!AircraftController(v)) {return;}

	AirportClearBlock(v, Airport);
	AirportMove(v, Airport); // move aircraft to next position
}

// gets pos from vehicle and next orders
static bool AirportMove(Vehicle *v, const AirportFTAClass *Airport)
{
	AirportFTA *current;
	byte prev_pos;
	bool retval = false;

	// error handling
	if (v->u.air.pos >= Airport->nofelements) {
		DEBUG(misc, 0) ("position %d is not valid for current airport. Max position is %d", v->u.air.pos, Airport->nofelements-1);
		assert(v->u.air.pos < Airport->nofelements);
	}

	current = &Airport->layout[v->u.air.pos];
	// we have arrived in an important state (eg terminal, hangar, etc.)
	if (current->heading == v->u.air.state) {
		prev_pos = v->u.air.pos; // location could be changed in state, so save it before-hand
		_aircraft_state_handlers[v->u.air.state](v, Airport);
		if (v->u.air.state != FLYING) {v->u.air.previous_pos = prev_pos;}
		return true;
	}

	v->u.air.previous_pos = v->u.air.pos; // save previous location

	// there is only one choice to move to
	if (current->next_in_chain == NULL) {
		if (AirportSetBlocks(v, current, Airport)) {
			v->u.air.pos = current->next_position;
		} // move to next position
		return retval;
	}

	// there are more choices to choose from, choose the one that
	// matches our heading
	do {
		if (v->u.air.state == current->heading || current->heading == TO_ALL) {
					if (AirportSetBlocks(v, current, Airport)) {
						v->u.air.pos = current->next_position;
					} // move to next position
					return retval;
		}
		current = current->next_in_chain;
	} while (current != NULL);

	DEBUG(misc, 0) ("Cannot move further on Airport...! pos:%d state:%d", v->u.air.pos, v->u.air.state);
	DEBUG(misc, 0) ("Airport entry point: %d, Vehicle: %d", Airport->entry_point, v->index);
	assert(0);
	return false;
}

// returns true if the road ahead is busy, eg. you must wait before proceeding
static bool AirportHasBlock(Vehicle *v, AirportFTA *current_pos, const AirportFTAClass *Airport)
{
	Station *st;
	uint32 airport_flags;
	AirportFTA *next, *reference;
	reference = &Airport->layout[v->u.air.pos];
	next = &Airport->layout[current_pos->next_position];

	// same block, then of course we can move
	if (Airport->layout[current_pos->position].block != next->block) {
		airport_flags = next->block;
		st = GetStation(v->u.air.targetairport);
		// check additional possible extra blocks
		if (current_pos != reference && current_pos->block != NOTHING_block) {
			airport_flags |= current_pos->block;
		}

		if (HASBITS(st->airport_flags, airport_flags)) {
			v->cur_speed = 0;
			v->subspeed = 0;
			return true;
		}
	}
	return false;
}

// returns true on success. Eg, next block was free and we have occupied it
static bool AirportSetBlocks(Vehicle *v, AirportFTA *current_pos, const AirportFTAClass *Airport)
{
	Station *st;
	uint32 airport_flags;
	AirportFTA *current, *reference, *next;
	next = &Airport->layout[current_pos->next_position];
	reference = &Airport->layout[v->u.air.pos];

	// if the next position is in another block, check it and wait until it is free
	if (Airport->layout[current_pos->position].block != next->block) {
		airport_flags = next->block;
		st = GetStation(v->u.air.targetairport);
		//search for all all elements in the list with the same state, and blocks != N
		// this means more blocks should be checked/set
		current = current_pos;
		if (current == reference) { current = current->next_in_chain;}
		while (current != NULL) {
			if (current->heading == current_pos->heading && current->block != 0) {
				airport_flags |= current->block;
				break;
			}
			current = current->next_in_chain;
		};

		// if the block to be checked is in the next position, then exclude that from
		// checking, because it has been set by the airplane before
		if (current_pos->block == next->block) {airport_flags ^= next->block;}

		if (HASBITS(st->airport_flags, airport_flags)) {
			v->cur_speed = 0;
			v->subspeed = 0;
			return false;
		}

		if (next->block != NOTHING_block) {
			SETBITS(st->airport_flags, airport_flags); // occupy next block
		}
	}
	return true;
}

static bool FreeTerminal(Vehicle *v, byte i, byte last_terminal)
{
	Station *st = GetStation(v->u.air.targetairport);
	for (; i < last_terminal; i++) {
		if (!HASBIT(st->airport_flags, i)) {
			// TERMINAL# HELIPAD#
			v->u.air.state = i + TERM1; // start moving to that terminal/helipad
			SETBIT(st->airport_flags, i); // occupy terminal/helipad
			return true;
		}
	}
	return false;
}

static int GetNumTerminals(const AirportFTAClass *Airport)
{
	int i, num = 0;

	for (i = Airport->terminals[0]; i > 0; i--)
		num += Airport->terminals[i];

	return num;
}

static bool AirportFindFreeTerminal(Vehicle *v, const AirportFTAClass *Airport)
{
	AirportFTA *temp;
	Station *st;

	/* example of more terminalgroups
		{0,HANGAR,NOTHING_block,1}, {0,255,TERM_GROUP1_block,0}, {0,255,TERM_GROUP2_ENTER_block,1}, {0,0,N,1},
		Heading 255 denotes a group. We see 2 groups here:
		1. group 0 -- TERM_GROUP1_block (check block)
		2. group 1 -- TERM_GROUP2_ENTER_block (check block)
		First in line is checked first, group 0. If the block (TERM_GROUP1_block) is free, it
		looks	at the corresponding terminals of that group. If no free ones are found, other
		possible groups are checked	(in this case group 1, since that is after group 0). If that
		fails, then attempt fails and plane waits
	*/
	if (Airport->terminals[0] > 1) {
		st = GetStation(v->u.air.targetairport);
		temp = Airport->layout[v->u.air.pos].next_in_chain;
		while (temp != NULL) {
			if (temp->heading == 255) {
				if (!HASBITS(st->airport_flags, temp->block)) {
					int target_group;
					int i;
					int group_start = 0;
					int group_end;

					//read which group do we want to go to?
					//(the first free group)
					target_group = temp->next_position + 1;

					//at what terminal does the group start?
					//that means, sum up all terminals of
					//groups with lower number
					for(i = 1; i < target_group; i++)
						group_start += Airport->terminals[i];

					group_end = group_start + Airport->terminals[target_group];
					if (FreeTerminal(v, group_start, group_end)) {return true;}
				}
			}
			else {return false;} // once the heading isn't 255, we've exhausted the possible blocks. So we cannot move
			temp = temp->next_in_chain;
		}
	}

	// if there is only 1 terminalgroup, all terminals are checked (starting from 0 to max)
	return FreeTerminal(v, 0, GetNumTerminals(Airport));
}

static int GetNumHelipads(const AirportFTAClass *Airport)
{
	int i, num = 0;

	for (i = Airport->helipads[0]; i > 0; i--)
		num += Airport->helipads[i];

	return num;
}


static bool AirportFindFreeHelipad(Vehicle *v, const AirportFTAClass *Airport)
{
  Station *st;
  AirportFTA *temp;

	// if an airport doesn't have helipads, use terminals
	if (Airport->helipads == NULL) {return AirportFindFreeTerminal(v, Airport);}

	// if there are more helicoptergroups, pick one, just as in AirportFindFreeTerminal()
	if (Airport->helipads[0] > 1) {
		st = GetStation(v->u.air.targetairport);
		temp = Airport->layout[v->u.air.pos].next_in_chain;
		while (temp != NULL) {
			if (temp->heading == 255) {
				if (!HASBITS(st->airport_flags, temp->block)) {
					int target_group;
					int i;
					int group_start = 0;
					int group_end;

					//read which group do we want to go to?
					//(the first free group)
					target_group = temp->next_position + 1;

					//at what terminal does the group start?
					//that means, sum up all terminals of
					//groups with lower number
					for(i = 1; i < target_group; i++)
						group_start += Airport->helipads[i];

					group_end = group_start + Airport->helipads[target_group];
					if (FreeTerminal(v, group_start, group_end)) {return true;}
				}
			}
			else {return false;} // once the heading isn't 255, we've exhausted the possible blocks. So we cannot move
			temp = temp->next_in_chain;
		}
	}
	// only 1 helicoptergroup, check all helipads
	// The blocks for helipads start after the last terminal (MAX_TERMINALS)
	else {return FreeTerminal(v, MAX_TERMINALS, GetNumHelipads(Airport) + MAX_TERMINALS);}
	return false;	// it shouldn't get here anytime, but just to be sure
}

static void AircraftEventHandler(Vehicle *v, int loop)
{
	v->tick_counter++;

	if (v->vehstatus & VS_CRASHED) {
		HandleCrashedAircraft(v);
		return;
	}

	/* exit if aircraft is stopped */
	if (v->vehstatus & VS_STOPPED)
		return;

	/* aircraft is broken down? */
	if (v->breakdown_ctr != 0) {
		if (v->breakdown_ctr <= 2) {
			HandleBrokenAircraft(v);
		} else {
			v->breakdown_ctr--;
		}
	}

	HandleAircraftSmoke(v);
	ProcessAircraftOrder(v);
	HandleAircraftLoading(v, loop);

	if (v->current_order.type >= OT_LOADING)
		return;

	// pass the right airport structure to the functions
	// DEREF_STATION gets target airport (Station *st), its type is passed to GetAirport
	// that returns the correct layout depending on type
	AirportGoToNextPosition(v, GetAirport(GetStation(v->u.air.targetairport)->airport_type));
}

void Aircraft_Tick(Vehicle *v)
{
	int i;

	if (v->subtype > 2)
		return;

	if (v->subtype == 0)
		HelicopterTickHandler(v);

	AgeAircraftCargo(v);

	for(i=0; i!=6; i++) {
		AircraftEventHandler(v, i);
		if (v->type != VEH_Aircraft) // In case it was deleted
			break;
	}
}

void UpdateOilRig( void )
{
	Station *st;

	FOR_ALL_STATIONS(st) {
		if (st->airport_type == 5) st->airport_type = AT_OILRIG;
	}
}

// need to be called to load aircraft from old version
void UpdateOldAircraft(void)
{
	Station *st;
	Vehicle *v_oldstyle;
	GetNewVehiclePosResult gp;

	// set airport_flags to 0 for all airports just to be sure
	FOR_ALL_STATIONS(st) {
		st->airport_flags = 0; // reset airport
		// type of oilrig has been moved, update it (3-5)
		if (st->airport_type == 3) {st->airport_type = AT_OILRIG;}
	}

	FOR_ALL_VEHICLES(v_oldstyle) {
	// airplane has another vehicle with subtype 4 (shadow), helicopter also has 3 (rotor)
	// skip those
		if (v_oldstyle->type == VEH_Aircraft && v_oldstyle->subtype <= 2) {
			// airplane in terminal stopped doesn't hurt anyone, so goto next
			if ((v_oldstyle->vehstatus & VS_STOPPED) && (v_oldstyle->u.air.state == 0)) {
				v_oldstyle->u.air.state = HANGAR;
				continue;
			}

			AircraftLeaveHangar(v_oldstyle); // make airplane visible if it was in a depot for example
			v_oldstyle->vehstatus &= ~VS_STOPPED; // make airplane moving
			v_oldstyle->u.air.state = FLYING;
			AircraftNextAirportPos_and_Order(v_oldstyle); // move it to the entry point of the airport
			GetNewVehiclePos(v_oldstyle, &gp); // get the position of the plane (to be used for setting)
			v_oldstyle->tile = 0; // aircraft in air is tile=0

			// correct speed of helicopter-rotors
			if (v_oldstyle->subtype == 0) {v_oldstyle->next->next->cur_speed = 32;}

			// set new position x,y,z
			SetAircraftPosition(v_oldstyle, gp.x, gp.y, GetAircraftFlyingAltitude(v_oldstyle));
		}
	}
}

void UpdateAirplanesOnNewStation(Station *st)
{
	GetNewVehiclePosResult gp;
	Vehicle *v;
	byte takeofftype;
	uint16 cnt;
	// only 1 station is updated per function call, so it is enough to get entry_point once
	const AirportFTAClass *ap = GetAirport(st->airport_type);
	FOR_ALL_VEHICLES(v) {
		if (v->type == VEH_Aircraft && v->subtype <= 2) {
			if (v->u.air.targetairport == st->index) {	// if heading to this airport
				/*	update position of airplane. If plane is not flying, landing, or taking off
						you cannot delete airport, so it doesn't matter
				*/
				if (v->u.air.state >= FLYING) {	// circle around
					v->u.air.pos = v->u.air.previous_pos = ap->entry_point;
					v->u.air.state = FLYING;
					// landing plane needs to be reset to flying height (only if in pause mode upgrade,
					// in normal mode, plane is reset in AircraftController. It doesn't hurt for FLYING
					GetNewVehiclePos(v, &gp);
					// set new position x,y,z
					SetAircraftPosition(v, gp.x, gp.y, GetAircraftFlyingAltitude(v));
				}
				else {
					assert(v->u.air.state == ENDTAKEOFF || v->u.air.state == HELITAKEOFF);
					takeofftype = (v->subtype == 0) ? HELITAKEOFF : ENDTAKEOFF;
					// search in airportdata for that heading
					// easiest to do, since this doesn't happen a lot
					for (cnt = 0; cnt < ap->nofelements; cnt++) {
						if (ap->layout[cnt].heading == takeofftype) {
							v->u.air.pos = ap->layout[cnt].position;
							break;
						}
					}
				}
			}
		}
	}
}