public JsonResult GetAvailability()
        {
            var availability = _aircraftService.GetAvailability();

            return(new JsonResult(availability.Select(av => new
            {
                availabilityId = av.Id,
                aircraftNumber = av.Aircraft.TailNumber,
                aircraftModel = av.Aircraft.Model.Name,
                aircraftType = av.Aircraft.Type.Name
            })
                                  .ToList()));
        }