You make a very good point, timex. Not only were Luftwaffe units withheld from the Eastern Front, but from the potential Western one as well. The D-Day troops had much to worry about but could at least be reassured that if they heard or saw an aircraft it would be one of ours. It was a damn close run thing anyway, so factoring in the missing Luftwaffe could have meant the difference between success and failure. Air superiority in the West had been bloodily one beforehand in the skies over Germany by day and night. A difficult concept for a sailor or a Tommy to grasp, meat and drink for any airman though, or so you would think. As to the Eastern Front, Kursk was the vital battle, where quantity had a quality all of its own, as the good Generalissimo said. Much is made of the increase in Nazi war production under round the clock bombing, but the point is that it didn't increase nearly enough, despite dispersal, despite civilian mobilisation, despite the brutal use of slave labour. Another vital effect of the bombing campaign. It is the final outcome that matters, and that was the invasion of the Reich from the East and the West. Both depended on Harris's lags. It was a war winning campaign.