If I bail it's because:
1. Someone already shot me down.
2. Something very important came up and there were no icons in range to fight (even just to give a kill to if it's so important it really just can't wait).
Other than that, I'll always try to get back to base - bingo, winchester, shot up, PW, whatever.
I don't get bomber-bailers (to avoid getting shot down by fighters), either (fighter-bailers, for that matter). I've been flying B-17s a lot this tour to see what's up. 20k + and you will never hardly see an enemy fighter take you on anywhere - even where the fight is (so all those guys posting they won't fly up to 20k to get bombers because it's a waste of time seems universal). 17k and you may get one. 15k and near any field with a fight and you'll get 2 or more (if they coordinate, good luck). 10kish or less and any enemy fighter in icon range will attack (at that point, if you ain't dropped you likely won't - concentrate on getting at least a kill or two). I had to fly the lower alts after a bit just to have a challenge. A buff jocky that's just out for score could potato it at 20k all day bombing towns without bailing.
Maybe it's that damned bailing accolade.