hmmm... what would I pick.
P-39D/Q (ground attack)
P-47D-40 (better than the -N unless it is long range)
Spit Mk. XVI (always need a good turner)
B-17 (always need bombers)
and the last plane is always a tough one for my needs. But I'm gonna pick....
F4U-4 (the best of the F4Us, great turner, best speed, Good altitude, average-great range, great ordinance) If I wanted, I could just make these fight and forget about the B-17s and replace them with something else if needed