Ok so while I was playing, I saw multiple aircraft that weren’t available in the airplane selection, such as the Supermarine Spitfire, the Messerschmitt ME-262, and even a P-40 Warhawk. How do you get these planes when they’re not even in the aircraft selection? Do you have to have a special rank, or is there a specific requirement in order to get these aircraft?

You need a rank and probably be a subscriber depending on the plane

ZUP the spawn kill is a great idea....but please define parameters.
Was coming into tbh with opponent already past the trees in German base and still got spawn killer deduction.
Where is the line????

It's mostly the amount of times you kill the same person in a given period. It tries to be smart about it but obviously sometimes it will fail. It's impossible to have it to always work, otherwise that wouldn't be a robot but an AI ala terminator.