499 /** Start/Stop an aircraft.

   500  * @param tile unused

   501  * @param flags for command type

   502  * @param p1 aircraft ID to start/stop

   503  * @param p2 unused

   504  * @return result of operation.  Nothing if everything went well

   505  */

   506 CommandCost CmdStartStopAircraft(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)

   507 {

   508 	if (!IsValidVehicleID(p1)) return CMD_ERROR;

   509 

   510 	Vehicle *v = GetVehicle(p1);

   511 

   512 	if (v->type != VEH_AIRCRAFT || !CheckOwnership(v->owner)) return CMD_ERROR;

   513 

   514 	/* cannot stop airplane when in flight, or when taking off / landing */

   515 	if (v->u.air.state >= STARTTAKEOFF && v->u.air.state < TERM7)

   516 		return_cmd_error(STR_A017_AIRCRAFT_IS_IN_FLIGHT);

   517 

   518 	/* Check if this aircraft can be started/stopped. The callback will fail or

   519 	 * return 0xFF if it can. */

   520 	uint16 callback = GetVehicleCallback(CBID_VEHICLE_START_STOP_CHECK, 0, 0, v->engine_type, v);

   521 	if (callback != CALLBACK_FAILED && GB(callback, 0, 8) != 0xFF) {

   522 		StringID error = GetGRFStringID(GetEngineGRFID(v->engine_type), 0xD000 + callback);

   523 		return_cmd_error(error);

   524 	}

   525 

   526 	if (flags & DC_EXEC) {

   527 		if (v->IsStoppedInDepot()) {

   528 			DeleteVehicleNews(p1, STR_A014_AIRCRAFT_IS_WAITING_IN);

   529 		}

   530 

   531 		v->vehstatus ^= VS_STOPPED;

   532 		v->cur_speed = 0;

   533 		InvalidateWindowWidget(WC_VEHICLE_VIEW, v->index, VVW_WIDGET_START_STOP_VEH);

   534 		InvalidateWindow(WC_VEHICLE_DEPOT, v->tile);

   535 		InvalidateWindowClasses(WC_AIRCRAFT_LIST);

   536 	}

   537 

   538 	return CommandCost();

   539 }

   540