diff --git a/src/station_cmd.cpp b/src/station_cmd.cpp
--- a/src/station_cmd.cpp
+++ b/src/station_cmd.cpp
@@ -1878,7 +1878,7 @@ static CommandCost RemoveAirport(TileInd
 
 	const Aircraft *a;
 	FOR_ALL_AIRCRAFT(a) {
-		if (!IsNormalAircraft(a)) continue;
+		if (!a->IsNormalAircraft()) continue;
 		if (a->targetairport == st->index && a->state != FLYING) return CMD_ERROR;
 	}