public async Task <ActionResult <FlightPlan> > PostFlightPlan(FlightPlan flightPlan)
{
_context.FlightPlan.Add(flightPlan);
//Generate a unique key for new flight.
do
{
flightPlan.FlightID = FlightPlan.GenerateFlightKey();
//As long as generated key is identical to a key in DB, generate a new one.
} while (_context.FlightPlan.Count(x => x.FlightID == flightPlan.FlightID) > 0);
await _context.SaveChangesAsync();
return(CreatedAtAction("GetFlightPlan", new { id = flightPlan.FlightID }, flightPlan));
}