Set Segoe UI Symbol font programmatically

The symbol for a right arrow is U+2192. The string you're using (✈) has been escaped so that it can be used in XAML. When using it in code, you use \u2192 to let it know that it's a symbol. So it should be

Text = "\u2192", //or \u2708 if you want the plane symbol

You can use string content = '\u2708'.ToString();