Not to sure about calibers bigger than 30mm being used on aircraft against others.
http://en.wikipedia.org/wiki/Hawker_Hurricane_variants - I think this was intended more for ground targets. i would have tried though aircraft to aircraft!!!
I am also sure there was a version of the é pounder that was used.
Fairly sure I posted here eons ago re a projectile I had that was a bit longer than the standard & I was informed it was for an aircraft mounted gun.
Obviously there is the 40mm bofors in the C130 Gunship - again this aircraft is for attacking ground targets.