ORIGINAL: ny59giants
The Allies get (if memory serves me right) 40 P-40E/mo, 16 Hurricane/mo, and soon about 40 to 45 F4F-4 Wildcats. The 'c' model Hurricane get 32/mo. I may be off in my numbers, but I'm close. By mid-42 the American Army fighter pilot pool is large (over 500) from all that go in from mandatory withdrawal and training. However, they cannot afford to get into too many lopsided A2A battles and lose 1/2 a month worth of planes. In my limited time playing Japan, I've learned that you need to aggressively seek out the Allied air force in combat. At least in '42 (I'm in May '43).
don't forget the P-39D (as good or better than the P-40E) and the P-400, better than both. Together with the reinforcements (downgrade/upgrade anyone? [:D]) you can build up a force of several hundred Allied frontline fighters by March/April 42 as I have done in my last PBEM. All these fighters were piloted by 70 skilled pilots and they chopped the Japanese to pieces as I've massed them instead of spreading them out on the whole map. If the Allied isn't willing to have his airframes dying bits and pieces and choses the place worth fighting then this can lead to quite significant IJ losses too.
If the IJ player isn't drastically ramping up his fighter production then the Allied aren't far away from total IJ numbers (of course every IJ player usually ramps up production to a great margin) and then much depends on the kill ratios. 1:1 sure favours the IJ but 1:2 or 1:3 for the IJ over an enemy base usually favours the Allied in both airframes and pilots.