public async override Task Delete <T>(T item)
{
if (item.id == 0)
{
throw new Exception();
}
if (typeof(T) == typeof(Aircraft))
{
InternalData.DeleteAircraft(InternalData.Lookups.Aircraft.FirstOrDefault(x => x.id == item.id));
}
if (typeof(T) == typeof(Airfield))
{
InternalData.DeleteAirfield(InternalData.Lookups.Airfields.FirstOrDefault(x => x.id == item.id));
}
if (typeof(T) == typeof(AcType))
{
InternalData.DeleteAcType(InternalData.Lookups.AcTypes.FirstOrDefault(x => x.id == item.id));
}
if (typeof(T) == typeof(Flight))
{
InternalData.DeleteFlight(InternalData.Flights.FirstOrDefault(x => x.id == item.id));
}
}