--- a/src/station_cmd.cpp	Fri Apr 25 01:39:33 2008 +0000
+++ b/src/station_cmd.cpp	Fri Apr 25 01:42:32 2008 +0000
@@ -1818,7 +1818,10 @@
 		 * 1. airport is upgraded
 		 * 2. airport is added to existing station (unfortunately unavoideable)
 		 */
-		if (airport_upgrade) UpdateAirplanesOnNewStation(st);
+		if (airport_upgrade) {
+			UpdateAirplanesOnNewStation(st);
+			DeallocateSpecFromFSMports(st, 1);
+		}
 
 		int fsmportspecindex = AllocateFSMportsSpecToStation(fsmportsspec, st, flags & DC_EXEC);
 		if (fsmportspecindex == -1) return CMD_ERROR;