Nuff said. A new special racing plane would probably be needed for this, though not necessary. I know the devs are very busy right now, but i hope one day the idea will be considered and implemented.
Feel free to lock/delete this if it's been suggested before
Edit: Another thought: you could probably Mario Kart it up by adding special missiles that when launched go up above the track, seek the player in first position and once they pass them close enough their engine becomes disabled or their air brakes pop out for a second or two to slow them down. Balloon/ballutte/quadcopter "mines" or decoys (like what F-35 uses) that are released and do the same thing except behind you. More lethal options like guns with live ammo would also be good if the players/track creator wants a proper death race. All that customizable and optional, of course.