To be fair I don't think it is like that. I often aim for wings/cockpit to get a quick kill and it seems to work okay. It may depend on the calibre of your guns, though. A 7.7 will be much, much less effective as a 20mm. And from what distance do you start shooting?
Yeah, maybe I need to wait until I see the white in their eyes, but that's what I play shooters for, not air combat games.