I had the same problem. I think the defaults are set to
mousewheel up=turn up
mousewheel down= turn down
w=accelerate
a & d =pitch left and right
space(i think)=drop bombs
left mouse =machine gun
e=parachute(i think)
I still haven't figured out how you're supposed to drop bombs and actually hit anything when all you can see is sky!
So far the most effective bet for me has been to simply fly the plane right into the target.
I still have tons of learning to do also. It all seemed pretty simple until i got to the battle of Iwa Jima where you must hold a majority of stratigic positions at any time and i think you MUST know how to fly the planes in order to win this one.