--- a/aircraft_cmd.c	Mon Jun 26 17:51:58 2006 +0000
+++ b/aircraft_cmd.c	Mon Jun 26 20:58:49 2006 +0000
@@ -219,8 +219,8 @@
 
 	// prevent building of aircraft in helidepot/helistation
 	st2 = GetStationByTile(tile);
-	if ((avi->subtype != 0) && (GetAirport(st2->airport_type)->acc_planes == HELICOPTERS_ONLY)) {
-		return_cmd_error(STR_ENGINE_NOT_BUILDABLE);
+	if ((avi->subtype & AIR_CTOL) && (GetAirport(st2->airport_type)->acc_planes == HELICOPTERS_ONLY)) {
+		return_cmd_error(STR_AIRPORT_HAS_NO_RUNWAY);
 	}
 
 	unit_num = (HASBIT(p2, 0) == true) ? 0 : GetFreeUnitNumber(VEH_Aircraft);

--- a/lang/english.txt	Mon Jun 26 17:51:58 2006 +0000
+++ b/lang/english.txt	Mon Jun 26 20:58:49 2006 +0000
@@ -2828,6 +2828,7 @@
 STR_REPLACE_ENGINE_WAGON_SELECT                                 :{BLACK}Replacing: {ORANGE}{SKIP}{SKIP}{STRING}
 STR_REPLACE_ENGINE_WAGON_SELECT_HELP                            :{BLACK} EXPERIMENTAL FEATURE {}Switch between engine and wagon replacement windows.{}Wagon replacement will only be done if the new wagon can be refitted into carrying the same type of cargo as the old one. This is checked for each wagon when the actual replacement takes place.
 STR_ENGINE_NOT_BUILDABLE                                        :{WHITE}Engine is not buildable
+STR_AIRPORT_HAS_NO_RUNWAY                                       :{WHITE}Airport has no runway
 
 STR_ENGINES                                                     :Engines
 STR_WAGONS                                                      :Wagons