Only ever thought Prox kills were designed to cover the situation where an enemy was outflown and forced into the ground.
Seems like there is no kill to deny, bailing over a friendly field from an undamaged plane 6000 yards from a vehicle that never fired a shot.
Quite a number of players would bail just deny their enemy a kill. That's also the reason proxy kill range was increased to icon display range a few years ago.
so closest enemy get the kill, if a vehicle is closer than an aircraft to the aircraft that smoked it in?