Masher, - the BIG thing that stalled the Germans in Barbarossa was the southern advance. Another big thing was the way they acted with their "cauldron battles", - i.e. instead of spearheading to the goals, they would tend to encircle the red army divisions and annihilate them.
When Guderian found out about the southern advance, he tried to change the plan, but without results. His goal was to grab Moscow ASAP, form a strongpoint there, and THEN head for the south, where the winter arrives later.
Now, of the red airforce, - their strenght was always more then Germany's in numbers. Even after thousands of aircraft were destroyed on the ground in the opening days of Barbarossa. Well, - that is one of the points in the lecture, - stacking up aircraft and airfields within shooting range from a borderline is a completely offensive setup, NOT defensive.
But as a true strength in the air, LW dominated in the beginning, and would have done so much more had it not been blood-drained so vigourously by the RAF.
Later, at the turning point at Stalingrad, the same problem actually occured. Operation Torch took place in the same period. In the frantic chaos of both battles, valuable transports, and more were sent FROM the Russian theatre to the med, in order to assist in the evacuation at Tunisia. It was in vain, - the allies had a field day in the air, and captured more than 300.000 POW's.
I once compared loss records from the LW (in the microfilm archive of the IWM) from Stalingrad and N-Africa. The losses seemed to be higher in N-Africa to my surprize, - but back then, I actually was finding out for the first time how big those events actually were.