Maybe Hitler sees sense and uses the BOB at a smaller scale,maybe to act as a diversion to keep pressure on the british,while the germans focus on more important areas[Malta,North africa,Balkans].
One way to make the battle shorter is in our timelime air marshal dowding successfully argued against deploying too much of the British Airforce in France.Had history gone differently and Churchill had not listened to him most of the british airforce would have been shot up on the ground on french airfields and would not have been availabe to fight the Luftwaffe in the battle of britain.
Had history gone differently and Churchill had not listened to him most of the british airforce would have been shot up on the ground on french airfields and would not have been availabe to fight the Luftwaffe in the battle of britain.
which might make the resulting battle _longer_. In extremis the RAF would have retreted to airbases in the north of England out of range of German bomber based in France and only sortied against an invasion or where there was a clear superiority. The RAF would be fighting less, but with less attrition. Of course the Germans would be hurting less and being more succesfull at bombing...
The French do marignally better in the inital stages of the war, and so accept union with Britain, and keep fighting in south of France, and evacuate the remainder of the French airfoce to Britain. The Luftwafe is far more exhausted by the start of the BoB, and the British lead time in construction is increased. The British then win the BoB shortly after it begins.
2 possibilities: Dowding orders actual co-operation with 11 Group, not just Park "requesting" aid from 12 Group, so the defense is stiffer. Or, Bomber Command uses its Beaus (& Battles?) in dawn/dusk intruder raids against (known!) German fighter/bomber bases in France, & smashes Luftflotte 2 in a matter of days.