diff --git a/src/station_base.h b/src/station_base.h
--- a/src/station_base.h
+++ b/src/station_base.h
@@ -302,7 +302,7 @@ struct Airport : public TileArea {
 	uint64 flags;       ///< stores which blocks on the airport are taken. was 16 bit earlier on, then 32
 	byte type;          ///< Type of this airport, @see AirportTypes
 	byte layout;        ///< Airport layout number.
-	Direction rotation; ///< How this airport is rotated.
+	DirectionByte rotation; ///< How this airport is rotated.
 
 	PersistentStorage *psa; ///< Persistent storage for NewGRF airports.