The Germans were never in a position to project air superiority over any theatre of operation except the Spanish Civil War and the initial stages of Blitzkreig in France and the Low Countries.
They simply lacked the numbers of pilots and aircraft needed to absolutely dominate and made up for this hugely in terms of quality, but if you read Steinhof's book, the Luftwaffe was exhausted by 1943 and being picked apart in detail. That doesn't diminish the losses suffered on both sides in any way, but many senior Luftwaffe staff knew they were screwed once Fatty Herman started projected his tactical doctrine into squadron operations. The Luftwaffe didn't rest its pilots either, hence the huge number of bomber missions and air to air kills racked up by German bomber and fighter crews.
The Eastern front was totally different to the Western Front. Most of the air fighting took place under 10,000ft and it was almost completely oriented around restricting logistics and and destroying AFVs and their supply train. The Luftwaffe got to "play" in this environment for a good 1.5 to 2 years before Russian numbers, training, and quality started to overwhelm the Luftwaffe. Most of the huge scores German aces ran up were on the Western Front. Hans Rudel was reputed (read his book - he claims a number of unrecognised air to air victories) to have shot down a number of fighter aircraft in Ju-87s, such was the quality of Russian pilot training.
In terms of your question though, by the time the Russian factories moved East beyond Urals were back in full production in 1943, the Soviets had almost complete air superiority and this showed in the number of Il2s fielded and Stalin's insistence on concentrating on ground attack aircraft. At one point Stalin was claimed to have preferred Il2 production over bread.
It is arguable that the Il2, the C47, the Russian Infantryman, and Liberty ships won WWII in Europe.
