--- a/src/ai/default/default.cpp	Tue Jul 24 21:54:45 2007 +0000
+++ b/src/ai/default/default.cpp	Tue Jul 24 22:16:32 2007 +0000
@@ -3409,7 +3409,7 @@
 
 	for (; p->mode == 0; p++) {
 		TileIndex tile2 = TILE_ADD(tile, ToTileIndexDiff(p->tileoffs));
-		AirportFTAClass* airport = GetAirport(p->attr);
+		const AirportFTAClass* airport = GetAirport(p->attr);
 		uint w = airport->size_x;
 		uint h = airport->size_y;
 		uint rad = _patches.modified_catchment ? airport->catchment : 4;

--- a/src/aircraft.h	Tue Jul 24 21:54:45 2007 +0000
+++ b/src/aircraft.h	Tue Jul 24 22:16:32 2007 +0000
@@ -58,7 +58,7 @@
 static inline bool IsAircraftBuildableAtStation(EngineID engine, TileIndex tile)
 {
 	const Station *st = GetStationByTile(tile);
-	AirportFTAClass *apc = st->Airport();
+	const AirportFTAClass *apc = st->Airport();
 	const AircraftVehicleInfo *avi = AircraftVehInfo(engine);
 
 	return (apc->flags & (avi->subtype & AIR_CTOL ? AirportFTAClass::AIRPLANES : AirportFTAClass::HELICOPTERS)) != 0;

--- a/src/aircraft_cmd.cpp	Tue Jul 24 21:54:45 2007 +0000
+++ b/src/aircraft_cmd.cpp	Tue Jul 24 22:16:32 2007 +0000
@@ -64,11 +64,11 @@
 	this->sprite_height = GB(x, 24, 8);
 }
 
-static bool AirportMove(Vehicle *v, AirportFTAClass *apc);
-static bool AirportSetBlocks(Vehicle *v, const AirportFTA *current_pos, AirportFTAClass *apc);
-static bool AirportHasBlock(Vehicle *v, const AirportFTA *current_pos, AirportFTAClass *apc);
-static bool AirportFindFreeTerminal(Vehicle *v, AirportFTAClass *apc);
-static bool AirportFindFreeHelipad(Vehicle *v, AirportFTAClass *apc);
+static bool AirportMove(Vehicle *v, const AirportFTAClass *apc);
+static bool AirportSetBlocks(Vehicle *v, const AirportFTA *current_pos, const AirportFTAClass *apc);
+static bool AirportHasBlock(Vehicle *v, const AirportFTA *current_pos, const AirportFTAClass *apc);
+static bool AirportFindFreeTerminal(Vehicle *v, const AirportFTAClass *apc);
+static bool AirportFindFreeHelipad(Vehicle *v, const AirportFTAClass *apc);
 static void CrashAirplane(Vehicle *v);
 
 static void AircraftNextAirportPos_and_Order(Vehicle *v);
@@ -108,7 +108,7 @@
 	FOR_ALL_STATIONS(st) {
 		if (st->owner != v->owner || !(st->facilities & FACIL_AIRPORT)) continue;
 
-		AirportFTAClass *afc = st->Airport();
+		const AirportFTAClass *afc = st->Airport();
 		if (afc->nof_depots == 0 || (
 					/* don't crash the plane if we know it can't land at the airport */
 					afc->flags & AirportFTAClass::SHORT_STRIP &&
@@ -387,7 +387,7 @@
 		 * of all depots, it is simple */
 		for (uint i = 0;; i++) {
 			const Station *st = GetStationByTile(tile);
-			AirportFTAClass *apc;
+			const AirportFTAClass *apc;
 			if (IsCustomFSMportsSpecIndex(tile)) {
 				apc = st->fsmportsspeclist[1].spec->portFSM;
 			} else {
@@ -1003,7 +1003,7 @@
  * @param apc The Airport Class being approached.
  * @returns   The index of the entry point
  */
-static byte AircraftGetEntryPoint(const Vehicle *v, AirportFTAClass *apc)
+static byte AircraftGetEntryPoint(const Vehicle *v, const AirportFTAClass *apc)
 {
 	assert(v != NULL);
 	assert(apc != NULL);
@@ -1037,7 +1037,7 @@
 {
 	int count;
 	const Station *st = GetStation(v->u.air.targetairport);
-	AirportFTAClass *afc = st->Airport();
+	const AirportFTAClass *afc = st->Airport();
 	const AirportMovingData *amd;
 
 	/* prevent going to 0,0 if airport is deleted. */
@@ -1515,7 +1515,7 @@
 			v->current_order.type == OT_GOTO_DEPOT)
 		v->u.air.targetairport = v->current_order.dest;
 
-	AirportFTAClass *apc = GetStation(v->u.air.targetairport)->Airport();
+	const AirportFTAClass *apc = GetStation(v->u.air.targetairport)->Airport();
 	v->u.air.pos = v->u.air.previous_pos = AircraftGetEntryPoint(v, apc);
 }
 
@@ -1548,20 +1548,20 @@
 ////////////////////////////////////////////////////////////////////////////////
 ///////////////////   AIRCRAFT MOVEMENT SCHEME  ////////////////////////////////
 ////////////////////////////////////////////////////////////////////////////////
-static void AircraftEventHandler_EnterTerminal(Vehicle *v, AirportFTAClass *apc)
+static void AircraftEventHandler_EnterTerminal(Vehicle *v, const AirportFTAClass *apc)
 {
 	AircraftEntersTerminal(v);
 	v->u.air.state = apc->layout[v->u.air.pos].heading;
 }
 
-static void AircraftEventHandler_EnterHangar(Vehicle *v, AirportFTAClass *apc)
+static void AircraftEventHandler_EnterHangar(Vehicle *v, const AirportFTAClass *apc)
 {
 	VehicleEnterDepot(v);
 	v->u.air.state = apc->layout[v->u.air.pos].heading;
 }
 
 /** In an Airport Hangar */
-static void AircraftEventHandler_InHangar(Vehicle *v, AirportFTAClass *apc)
+static void AircraftEventHandler_InHangar(Vehicle *v, const AirportFTAClass *apc)
 {
 	/* if we just arrived, execute EnterHangar first */
 	if (v->u.air.previous_pos != v->u.air.pos) {
@@ -1600,7 +1600,7 @@
 }
 
 /** At one of the Airport's Terminals */
-static void AircraftEventHandler_AtTerminal(Vehicle *v, AirportFTAClass *apc)
+static void AircraftEventHandler_AtTerminal(Vehicle *v, const AirportFTAClass *apc)
 {
 	/* if we just arrived, execute EnterTerminal first */
 	if (v->u.air.previous_pos != v->u.air.pos) {
@@ -1646,31 +1646,31 @@
 	AirportMove(v, apc);
 }
 
-static void AircraftEventHandler_General(Vehicle *v, AirportFTAClass *apc)
+static void AircraftEventHandler_General(Vehicle *v, const AirportFTAClass *apc)
 {
 	assert("OK, you shouldn't be here, check your Airport Scheme!" && 0);
 }
 
-static void AircraftEventHandler_TakeOff(Vehicle *v, AirportFTAClass *apc)
+static void AircraftEventHandler_TakeOff(Vehicle *v, const AirportFTAClass *apc)
 {
 	PlayAircraftSound(v); // play takeoffsound for airplanes
 	v->u.air.state = STARTTAKEOFF;
 }
 
-static void AircraftEventHandler_StartTakeOff(Vehicle *v, AirportFTAClass *apc)
+static void AircraftEventHandler_StartTakeOff(Vehicle *v, const AirportFTAClass *apc)
 {
 	v->u.air.state = ENDTAKEOFF;
 	v->UpdateDeltaXY(INVALID_DIR);
 }
 
-static void AircraftEventHandler_EndTakeOff(Vehicle *v, AirportFTAClass *apc)
+static void AircraftEventHandler_EndTakeOff(Vehicle *v, const AirportFTAClass *apc)
 {
 	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, AirportFTAClass *apc)
+static void AircraftEventHandler_HeliTakeOff(Vehicle *v, const AirportFTAClass *apc)
 {
 	const Player* p = GetPlayer(v->owner);
 	v->u.air.state = FLYING;
@@ -1692,7 +1692,7 @@
 	}
 }
 
-static void AircraftEventHandler_Flying(Vehicle *v, AirportFTAClass *apc)
+static void AircraftEventHandler_Flying(Vehicle *v, const AirportFTAClass *apc)
 {
 	Station *st = GetStation(v->u.air.targetairport);
 
@@ -1731,7 +1731,7 @@
 	v->u.air.pos = apc->layout[v->u.air.pos].next_position;
 }
 
-static void AircraftEventHandler_Landing(Vehicle *v, AirportFTAClass *apc)
+static void AircraftEventHandler_Landing(Vehicle *v, const AirportFTAClass *apc)
 {
 	v->u.air.state = ENDLANDING;
 	AircraftLandAirplane(v);  // maybe crash airplane
@@ -1750,13 +1750,13 @@
 	}
 }
 
-static void AircraftEventHandler_HeliLanding(Vehicle *v, AirportFTAClass *apc)
+static void AircraftEventHandler_HeliLanding(Vehicle *v, const AirportFTAClass *apc)
 {
 	v->u.air.state = HELIENDLANDING;
 	v->UpdateDeltaXY(INVALID_DIR);
 }
 
-static void AircraftEventHandler_EndLanding(Vehicle *v, AirportFTAClass *apc)
+static void AircraftEventHandler_EndLanding(Vehicle *v, const AirportFTAClass *apc)
 {
 	/* next block busy, don't do a thing, just wait */
 	if (AirportHasBlock(v, &apc->layout[v->u.air.pos], apc)) return;
@@ -1772,7 +1772,7 @@
 
 }
 
-static void AircraftEventHandler_HeliEndLanding(Vehicle *v, AirportFTAClass *apc)
+static void AircraftEventHandler_HeliEndLanding(Vehicle *v, const AirportFTAClass *apc)
 {
 	/*  next block busy, don't do a thing, just wait */
 	if (AirportHasBlock(v, &apc->layout[v->u.air.pos], apc)) return;
@@ -1790,7 +1790,7 @@
 	v->u.air.state = (apc->nof_depots != 0) ? HANGAR : HELITAKEOFF;
 }
 
-typedef void AircraftStateHandler(Vehicle *v, AirportFTAClass *apc);
+typedef void AircraftStateHandler(Vehicle *v, const AirportFTAClass *apc);
 static AircraftStateHandler * const _aircraft_state_handlers[] = {
 	AircraftEventHandler_General,        // TO_ALL         =  0
 	AircraftEventHandler_InHangar,       // HANGAR         =  1
@@ -1817,7 +1817,7 @@
 	AircraftEventHandler_AtTerminal,     // HELIPAD4       = 22
 };
 
-static void AirportClearBlock(const Vehicle *v, AirportFTAClass *apc)
+static void AirportClearBlock(const Vehicle *v, const AirportFTAClass *apc)
 {
 	/* we have left the previous block, and entered the new one. Free the previous block */
 	if (apc->layout[v->u.air.previous_pos].block != apc->layout[v->u.air.pos].block) {
@@ -1832,14 +1832,14 @@
 	/* if aircraft is not in position, wait until it is */
 	if (!AircraftController(v)) return;
 
-	AirportFTAClass *apc = GetStation(v->u.air.targetairport)->Airport();
+	const AirportFTAClass *apc = GetStation(v->u.air.targetairport)->Airport();
 
 	AirportClearBlock(v, apc);
 	AirportMove(v, apc); // move aircraft to next position
 }
 
 /* gets pos from vehicle and next orders */
-static bool AirportMove(Vehicle *v, AirportFTAClass *apc)
+static bool AirportMove(Vehicle *v, const AirportFTAClass *apc)
 {
 	/* error handling */
 	if (v->u.air.pos >= apc->nofelements) {
@@ -1888,7 +1888,7 @@
 }
 
 /*  returns true if the road ahead is busy, eg. you must wait before proceeding */
-static bool AirportHasBlock(Vehicle *v, const AirportFTA *current_pos, AirportFTAClass *apc)
+static bool AirportHasBlock(Vehicle *v, const AirportFTA *current_pos, const AirportFTAClass *apc)
 {
 	const AirportFTA *reference = &apc->layout[v->u.air.pos];
 	const AirportFTA *next = &apc->layout[current_pos->next_position];
@@ -1919,7 +1919,7 @@
  * @param apc airport on which block is requsted to be set
  * @returns true on success. Eg, next block was free and we have occupied it
  */
-static bool AirportSetBlocks(Vehicle *v, const AirportFTA *current_pos, AirportFTAClass *apc)
+static bool AirportSetBlocks(Vehicle *v, const AirportFTA *current_pos, const AirportFTAClass *apc)
 {
 	const AirportFTA *next = &apc->layout[current_pos->next_position];
 	const AirportFTA *reference = &apc->layout[v->u.air.pos];
@@ -1970,7 +1970,7 @@
 	return false;
 }
 
-static uint GetNumTerminals(AirportFTAClass *apc)
+static uint GetNumTerminals(const AirportFTAClass *apc)
 {
 	uint num = 0;
 
@@ -1979,7 +1979,7 @@
 	return num;
 }
 
-static bool AirportFindFreeTerminal(Vehicle *v, AirportFTAClass *apc)
+static bool AirportFindFreeTerminal(Vehicle *v, const AirportFTAClass *apc)
 {
 	/* 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},
@@ -2026,7 +2026,7 @@
 	return FreeTerminal(v, 0, GetNumTerminals(apc));
 }
 
-static uint GetNumHelipads(AirportFTAClass *apc)
+static uint GetNumHelipads(const AirportFTAClass *apc)
 {
 	uint num = 0;
 
@@ -2036,7 +2036,7 @@
 }
 
 
-static bool AirportFindFreeHelipad(Vehicle *v, AirportFTAClass *apc)
+static bool AirportFindFreeHelipad(Vehicle *v, const AirportFTAClass *apc)
 {
 	/* if an airport doesn't have helipads, use terminals */
 	if (apc->helipads == NULL) return AirportFindFreeTerminal(v, apc);
@@ -2169,7 +2169,7 @@
 void UpdateAirplanesOnNewStation(const Station *st)
 {
 	/* only 1 station is updated per function call, so it is enough to get entry_point once */
-	AirportFTAClass *ap = st->Airport();
+	const AirportFTAClass *ap = st->Airport();
 
 	Vehicle *v;
 	FOR_ALL_VEHICLES(v) {

--- a/src/airport.cpp	Tue Jul 24 21:54:45 2007 +0000
+++ b/src/airport.cpp	Tue Jul 24 22:16:32 2007 +0000
@@ -466,7 +466,7 @@
 }
 #endif
 
-AirportFTAClass *GetAirport(const byte airport_type)
+const AirportFTAClass *GetAirport(const byte airport_type)
 {
 	//FIXME -- AircraftNextAirportPos_and_Order -> Needs something nicer, don't like this code
 	// needs constant change if more airports are added

--- a/src/airport.h	Tue Jul 24 21:54:45 2007 +0000
+++ b/src/airport.h	Tue Jul 24 22:16:32 2007 +0000
@@ -68,7 +68,7 @@
 
 		~AirportFTAClass();
 
-		AirportMovingData *MovingData(byte position)
+		const AirportMovingData *MovingData(byte position) const
 		{
 			assert(position < nofelements);
 			return &moving_data[position];
@@ -103,7 +103,7 @@
 
 void InitializeAirports();
 void UnInitializeAirports();
-AirportFTAClass *GetAirport(const byte airport_type);
+const AirportFTAClass *GetAirport(const byte airport_type);
 
 /** Get buildable airport bitmask.
  * @return get all buildable airports at this given time, bitmasked.

--- a/src/airport_gui.cpp	Tue Jul 24 21:54:45 2007 +0000
+++ b/src/airport_gui.cpp	Tue Jul 24 22:16:32 2007 +0000
@@ -181,7 +181,7 @@
 
 		int i; // airport enabling loop
 		uint32 avail_airports;
-		AirportFTAClass *airport;
+		const AirportFTAClass *airport;
 
 		if (WP(w, def_d).close) return;
 

--- a/src/newgrf_engine.cpp	Tue Jul 24 21:54:45 2007 +0000
+++ b/src/newgrf_engine.cpp	Tue Jul 24 22:16:32 2007 +0000
@@ -248,7 +248,7 @@
 	const Station *st = GetStation(v->u.air.targetairport);
 	if (st->airport_tile == 0) return AMS_TTDP_FLIGHT_TO_TOWER;
 
-	AirportFTAClass *afc = st->Airport();
+	const AirportFTAClass *afc = st->Airport();
 	uint16 amdflag = afc->MovingData(v->u.air.pos)->flag;
 
 	switch (v->u.air.state) {

--- a/src/station.h	Tue Jul 24 21:54:45 2007 +0000
+++ b/src/station.h	Tue Jul 24 22:16:32 2007 +0000
@@ -119,7 +119,7 @@
 			return type == RoadStop::BUS ? bus_stops : truck_stops;
 		}
 
-		AirportFTAClass *Airport() const
+		const AirportFTAClass *Airport() const
 		{
 			if (airport_tile == 0) return GetAirport(AT_DUMMY);
 			return GetAirport(airport_type);

--- a/src/station_cmd.cpp	Tue Jul 24 21:54:45 2007 +0000
+++ b/src/station_cmd.cpp	Tue Jul 24 22:16:32 2007 +0000
@@ -494,7 +494,7 @@
 	}
 
 	if (st->airport_tile != 0) {
-		AirportFTAClass* afc = st->Airport();
+		const AirportFTAClass* afc = st->Airport();
 
 		MergePoint(&rect, st->airport_tile);
 		MergePoint(&rect,
@@ -1531,7 +1531,7 @@
 		}
 	}
 
-	AirportFTAClass *afc = GetAirport(original_airport_type);
+	const AirportFTAClass *afc = GetAirport(original_airport_type);
 	int w = afc->size_x;
 	int h = afc->size_y;
 
@@ -1667,7 +1667,7 @@
 {
 	int w, h;
 	const FSMportsSpec *fsmportsspec;
-	AirportFTAClass *afc;
+	const AirportFTAClass *afc;
 
 	if (_current_player != OWNER_WATER && !CheckOwnership(st->owner))
 		return CMD_ERROR;

--- a/src/water_cmd.cpp	Tue Jul 24 21:54:45 2007 +0000
+++ b/src/water_cmd.cpp	Tue Jul 24 22:16:32 2007 +0000
@@ -616,7 +616,7 @@
 {
 	if (IsTileType(tile, MP_STATION) && IsAirport(tile)) {
 		const Station *st = GetStationByTile(tile);
-		AirportFTAClass *airport = st->Airport();
+		const AirportFTAClass *airport = st->Airport();
 		for (uint x = 0; x < airport->size_x; x++) {
 			for (uint y = 0; y < airport->size_y; y++) {
 				tile = TILE_ADDXY(st->airport_tile, x, y);
@@ -660,7 +660,7 @@
 				 * that station has a big z_offset for the aircraft. */
 				if (!IsTileType(v->tile, MP_STATION) || !IsAirport(v->tile) || GetTileMaxZ(v->tile) != 0) return;
 				const Station *st = GetStationByTile(v->tile);
-				AirportFTAClass *airport = st->Airport();
+				const AirportFTAClass *airport = st->Airport();
 
 				if (v->z_pos != airport->delta_z + 1) return;
 			}