/*
         * delete flight plan from the server.
         */
        public async Task <ActionResult> Delete(string id)
        {
            FlightPlan fp = await _fpDb.LoadFP(id);

            if (fp == null)
            {
                return(NotFound());
            }
            if (await _flightToServerDb.IsFlightExternal(id))
            {
                return(BadRequest());
            }
            await _fpDb.DeleteFlight(id);

            await _flightToServerDb.DeleteFlightToServer(id);

            return(Ok());
        }