diff --git a/src/newgrf_airporttiles.h b/src/newgrf_airporttiles.h
--- a/src/newgrf_airporttiles.h
+++ b/src/newgrf_airporttiles.h
@@ -38,8 +38,8 @@ struct AirportTileScopeResolver : public
 		this->airport_id = st->airport.type;
 	}
 
-	/* virtual */ uint32 GetRandomBits() const;
-	/* virtual */ uint32 GetVariable(byte variable, uint32 parameter, bool *available) const;
+	uint32 GetRandomBits() const override;
+	uint32 GetVariable(byte variable, uint32 parameter, bool *available) const override;
 };
 
 /** Resolver for tiles of an airport. */
@@ -49,7 +49,7 @@ struct AirportTileResolverObject : publi
 	AirportTileResolverObject(const AirportTileSpec *ats, TileIndex tile, Station *st,
 			CallbackID callback = CBID_NO_CALLBACK, uint32 callback_param1 = 0, uint32 callback_param2 = 0);
 
-	/* virtual */ ScopeResolver *GetScope(VarSpriteGroupScope scope = VSG_SCOPE_SELF, byte relative = 0)
+	ScopeResolver *GetScope(VarSpriteGroupScope scope = VSG_SCOPE_SELF, byte relative = 0) override
 	{
 		switch (scope) {
 			case VSG_SCOPE_SELF: return &tiles_scope;