//changes the demand between two airports public static void ChangePaxDemand(Airport airport1, Airport airport2, int value) { DestinationDemand destPax = airport1.GetDestinationPassengersObject(airport2); if (destPax != null && value > 0) { destPax.Rate += Convert.ToUInt16(value); } else { if (value > 0) { airport1.AddDestinationPassengersRate(airport2, Convert.ToUInt16(value)); } } }