My & some friends of mine are trying to think of the name of an old Sega game we used to play (Epic fail on our part), and thought we'd shout out here since nobody seems to know it.
I'm pretty sure it was for Genesis/Mega Drive. It was an airplane shoot 'em up vertical scroller. My memory is kind of fuzzy about it, but I remember that it wasn't an old prop plane or anything like that; it was more of a modern fighter jet with after burners & stuff. It wasn't set in outer space though- I remember flying over what looked like trees and water and such.
One distinguishing feature unique to this game was these little "helper" invincible airplanes that you get as a powerup. I remember you get 2 of them and one of the controller buttons lets you position them either in front of, behind, immediately beside, or far to either side of your own plane. I usually put them in front because they are invincible and most attacks came from that direction.