diff --git a/src/station_cmd.cpp b/src/station_cmd.cpp
--- a/src/station_cmd.cpp
+++ b/src/station_cmd.cpp
@@ -1968,7 +1968,7 @@ static CommandCost RemoveAirport(Station
 	FOR_ALL_VEHICLES(v) {
 		if (!(v->type == VEH_AIRCRAFT && IsNormalAircraft(v))) continue;
 
-		Aircraft *a = (Aircraft *)v;
+		const Aircraft *a = (const Aircraft *)v;
 		if (a->targetairport == st->index && a->state != FLYING) return CMD_ERROR;
 	}