When I tried it in someone else's server, firing while flying quickly can self-destruct your plane or kill passengers. (In stunt plane and biplane, occasionally)
EDIT: Also, the firing sound plays whether you're in a vehicle or not, but nothing actually appears.
Yes, the bombs always fall at the bottom of the player, so you can't fire them when at an angle. As long as you're not swirling around while bombing, you'll be okay.
Also, that isn't much of a bug.
Fail.
What the forget are you talking about?
OffTopic:
How come you make great add-ons and stuff, your nice in-game, but you flame your ass off on the forums? T_T
=
It's just what I do.