--- a/aircraft_cmd.c	Sat Jun 04 07:36:28 2005 +0000
+++ b/aircraft_cmd.c	Sat Jun 04 11:56:32 2005 +0000
@@ -178,7 +178,7 @@
 	// Workaround: TODO: make AI players try to build planes in a hangar instead of just an airport tile.
 	if (!IsAircraftHangarTile(tile) && IS_HUMAN_PLAYER(_current_player)) return CMD_ERROR;
 
-	if (_map_owner[tile] != _current_player && IS_HUMAN_PLAYER(_current_player)) return CMD_ERROR;
+	if (!IsTileOwner(tile, _current_player) && IS_HUMAN_PLAYER(_current_player)) return CMD_ERROR;
 
 	SET_EXPENSES_TYPE(EXPENSES_NEW_VEHICLES);