Seriously...is this really an issue??? Keep your clipboard up on screen so you can see an incoming plane icon due to proximity dar. Use your situational awareness in general. I'll be the first to admit I get pissed when I get jumped, but it's not due to lack of hearing the sound of the aircraft.
While it may be poor sportsmanship to use this tactic it's how players game the game. No different than certain GV'ers that have their sounds tweaked, turn down graphics, use gamma, etc etc.
You wanna fix something - get rid of the GVDar and the proximity radar for planes to start. Those 2 things alone killed off missions, lost players to the game and has far more of an effect.