(svn r8973) -Feature/Codechange: Changed the internal unit for aircraft velocities to from 8mph to 1km/h (peter1138), also give aircraft realsitic velocities (so that 1km/h is 1km/h independent of vehicle type) (peter1138). Introduce a flag to reduce aircraft speed in holding patterns to some realistic velocity. Use this flag for the city airport for the time being and make use of the different entry points for this airport type.

src/airport.h

@@ -36,6 +36,7 @@ enum {
 	AMED_BRAKE      = 1 << 5,
 	AMED_HELI_RAISE = 1 << 6,
 	AMED_HELI_LOWER = 1 << 7,
+	AMED_HOLD       = 1 << 8
 };
 
 /* Movement States on Airports (headings target) */
@@ -114,7 +115,7 @@ static const uint64
 typedef struct AirportMovingData {
 	int16 x;
 	int16 y;
-	byte flag;
+	uint16 flag;
 	DirectionByte direction;
 } AirportMovingData;