For me both are right.. Right before you shoot lead'em.. then once they are in the air.. lock on them and stay on them.. even if you can't see them.. I have torched a few that thought they got away..
Speaking of which I got a punishment for a TK because I shoot down a helo and the fool that was trying to fight them with a machine gun was right underneath so when the helo was shoot down it landed right on top of killing him thus giving me a TK.. ooppss so sorry was trying to protect me flag..
Silver