As it is well known, the Allied advance through France was delayed by long supply lines. This one is politically ASB, but somewhat feasible technically:
What if, realising the unique chance for true "blitzkrieg" it is decided that bombing campaign against Germany is suspended for a month on beginning of August 1944 and the main airborne strength of 8th Air Force and RAF Bomber Command bombers are used for resupplying spearheads and airheads of advance? Although the heavy bombers were not ideal cargo planes, they could still deliver a very significant amount of supplies via parachuting and also to airfields when captured. Historically bombers were used in Operation Manna during the last days of Second World War to supply Dutch population with food.
1st US Army used some 800,000 gallons of fuel per day during highly mobile operations, or some 5 000 000 pounds. Multiply this by three (for 2nd British and 3rd US Army) and you get some 15 000 000 pounds of fuel. This is equivalent of some 750 fully laden Lancaster bomber bombloads. What would have been a practical amount to carry I don't know, but considering that fuel could have been delivered rather directly to advancing units should have counted something, as well as the fact that 750 Lancasters would have been just a portion of the vast Allied bomber force. Moreover, a sortie rate higher than one per day could be envisioned due to less strain of cargo mission and shorter length of flights.
Naturally much more than just fuel would have been needed. An American division in Normandy was calculated to need a total of 640 tons of supplies per day, or equivalent of 64 Lancaster sorties in bombload terms. This was the requirement in breakthrough battles requiring a lot of ammunition. What the volume terms or sortie rate would have been I don't have an idea. Naturally a lot would have been supplied via traditional overland route as in OTL.
As even smaller portion of Allied heavy bomber strength, and above all, fighters, could have kept the Luftwaffe defending the Reich at bay, I don't know if there would have been any pro-sides for Germany due to this policy.
But anyway, does anyone have thoughts about this?