Really so RAF had air superiority in NW Europe from summer 41... Never heard that position stated before. I know that they had established dominance over The British Islands, but even the Channel was still hotly contested in late 42 to mid 43, little own the bulk of western Europe. Air Supremecy existed for all of France and much of western Germany by DDay of course, it was a requirment of invasion. But Barbarosa to Overlord is nearly 3 years. And during that time the RAF + attachments and for much of it the USAAF where opposed I believe by 2 understrength wings of fighters. JG26 and JG2
With (according to AH) inferior fighters.
I guess they only engaged from very favorable conditions.