Asking for mercy is pretty sad. And then getting angry because it was not given is even worse. You made your request and it was not granted. Get over it.

This game to me is about kills. Sometimes I let fueless/engineless planes go and sometimes I don't.

In my not so humble opinion if you let yourself run out of fuel in a postition where your opponent can easily catch you then you have made some seriously bad play decisions. When you do that in a dogfight you will pay. If you don't want to be shot down when gliding then get the heck off the board before you run out of FUEL!!!!!!