(svn r14385) [0.6] -Backport from trunk:

- Fix: Invalid v->u.air.targetairport could cause crashes at several places [FS#2300] (r14383, r14344, r14343)
- Fix: Moving the first vehicle of a train elsewhere might require a new unitnumber for the remaining chain which might not be available (r14384)
- Fix: Trams jumping when reversing on a single trambit (like caused during road construction reworks) or when (manually) reversing in a corner [FS#1852] (r14371)
- Fix: Multiheaded parts in free wagon chains weren't connected (could cause desyncs) (r14366, r14362)
- Fix: [Win32] Some keypress combinations could be handled twice [FS#2206] (r14363)
- Fix: The ownership of roadtiles was not properly set for very old savegames (including TTD's) making it impossible to remove some pieces of road [FS#2311] (r14359)
- Fix: Desync due to randomly ordered vehicle hash by flooding and road vehicle overtake/following (r14356, r14258)
- Fix: Signs were not updated on company bankrupcy/sell, and thus could have the colour of invalid player (r14348)
- Fix: Delete the RenameSignWindow when 'its' sign is deleted (r14345)

src/aircraft_cmd.cpp

@@ -1059,10 +1059,8 @@ static bool AircraftController(Vehicle *v)
 {
 	int count;
 
-	StationID target = v->u.air.targetairport;
-
 	/* NULL if station is invalid */
-	const Station *st = IsValidStationID(target) ? GetStation(target) : NULL;
+	const Station *st = IsValidStationID(v->u.air.targetairport) ? GetStation(v->u.air.targetairport) : NULL;
 	/* 0 if there is no station */
 	TileIndex tile = 0;
 	if (st != NULL) {