How effective was the (Western) Allies bombing campaign over Germany in drawing down the Eastern Front Luftwaffe?

Question

The strategic air campaign over Germany by 8th US Air Force and "Bomber Harris" for the RAF has elicited decidedly mixed opinions. Depending on who you listen to it was a noble effort or it was a waste.

Allied airmen losses were horrendous, German civilian deaths massive and German industrial output actually rose (albeit probably due to the rationalization efforts of Todt and Speer).

At the same time, it is true that, after Dieppe, the alternatives of a true second front in continental Europe were limited, so that bombing was probably one of the few way to strike at Germany.

However, we also know that the Luftwaffe gradually lost its air superiority on the Eastern Front which made Germany's situation there ever more untenable.

Is there any study that quantifies how much of a Westward shift of German fighters happened from early Barbarossa to say late 43, once Allied bombing really got underway? Were the Allied raids a major cause to the gradual weakening of the East Front Luftwaffe?

Please, I am not asking about the losses suffered by Luftwaffe transports during Stalingrad. This is about losing control of the skies, i.e. weakening ME109/FW190 availability over Russia because of transfer to protect Germany.

Edit: it's not specifically about moving planes around, East to West. Allocation of replacement planes and pilots, even fuel allocation, if shortages resulted in less Luftwaffe activity in the East. In a roundabout way, even prioritization of design and production of bomber-destroying aircraft, like the ME163, would have affected the East front.

Basically, how many Luftwaffe resources, defined broadly, do we see used to protect Germany, as opposed to used elsewhere, the most important other location being beating the Red Army on the ground and in the air?

Answer 1

There were two key effects of the strategic bombing campaign for the composition and deployment of the Luftwaffe. The first was the shift in production to emphasise fighters for defence, with a resultant decrease in bomber production (in March 1943 962 fighters and 757 bombers were produced; in December 1944 it was 2,630 fighters and 262 bombers), and thus reduction in offensive capability. The second was the shift of units to defend Germany. In the first half of 1943 45% of the Luftwaffe was on the Eastern Front, 33% was on the Western Front and/or defending Germany, 21% was in the Mediterranean. As the Combined Bomber Offensive started in earnest, by the end of 1943 54% of the Luftwaffe was on the Western Front and/or defending Germany; by the end of the following year it was 67%. The distribution of fighters was even more skewed, in the second half of 1944 less than one fifth of German fighters were on the Eastern Front.

Anti-aircraft defences also absorbed massive totals of personnel and weapons that could otherwise have been employed on the front; 889,000 personnel operating 14,400 heavy and 42,000 light guns, consuming one-fifth of all ammunition, half the production of the electronics industry, and one-third of optical equipment.

Figures are from Phillips Payson O'Brien's How The War Was Won: Air-Sea Power and Allied Victory in World War II and Richard Overy's The Bombing War: Europe 1939-1945.