What counts as a 'bomber' in strike?

[NephilimUK]

Since I have already unlocked the B17, (by flying bona-fide bombers and winning 50 games), I am putting this question for the benefit of my gaming buddies who do not relish being a big target (cowards ) and can't seem to get the hang of using the defensive armament, preferring to whizz around in Stuka's..

As far as I can gather, simply having a plane that can drop a bomb or two does not count..

Whilst I'm on the subject, wtf is it with everyone choosing fighters in games of strike? - I know that it's a cheap way of racking up some (easier) kills - but surely, helping your team get a win is just as important?