True but the step from MkI to MkII was not as major as the step from E to F types of the Me 109. Especially the implications on tooling and thus production. But point taken, new types were being introduced all the time by all major airforces. The more interesting data would be how large the pilot output was, something Germany struggled with throughout all the war. No pilots available -> no planes needed.Riacrato
True but so was the RAF. Spit II had more or less replaced the Spit Ia and the Spit V was entering service from February 1941. The Hurricane II was replacing the MkI and the changes to the nightfighters were probably more extensive in the RAF with the Beaufighter being introduced. The Short Sterling entered service in the first half of 1941, I could go on. The point is that there was no excuse for the Luftwaffe to be so poorly prepared.
And poorly prepared for what? Barbarossa was the main offensive in 1941. The German LW had numeric superior in all important branches if you count only non-obsolete types. And they destroyed the majority of the VVS within weeks. So bad that they enjoyed air superiority much longer than the ground forces could keep their advantage. In the west they did fine, too. Things started changing mid 1942, but no 1940-1941 production would've helped with that.