public static object ShowPopUp(FleetAirliner airliner)
        {
            PopUpNewAirlinerHomeBase window = new PopUpNewAirlinerHomeBase(airliner);
            window.ShowDialog();

            return window.Selected == null ? null : window.Selected;
        }
        public static object ShowPopUp(FleetAirliner airliner)
        {
            PopUpNewAirlinerHomeBase window = new PopUpNewAirlinerHomeBase(airliner);

            window.ShowDialog();

            return(window.Selected == null ? null : window.Selected);
        }