Mark and Russ, you are right about German aircraft production. But Jacques already said that German aircraft production WASN'T the problem (of course, there are these feudal-like relations between the German high-command and industry that cause problems).
The longer and harder battle of France will already have triggered things on the German side.
But note that in OTL, the Germans never really had a problem with aircraft production (until the end of the war).

The main problem is with pilots. The Germans won't recover 900+ experienced aircrews, which have fought in Spain, Poland and in the West. This will wreak havoc in the training program (because captured experienced crews won't go back to school to teach lessons). This will be felt at the end of 1942/beginning of 1943.
Of course, the German will increase their training program, but continuous fighting in the Med AND of course Barbarossa against a MUCH tougher opponent will quicky absorb the surplus of green pilots.

Another problem is aviation fuel (Ploesti).