HiI suppose, but had Britain been successfully invaded by the Germans I'd like to think that British, Imperial and Commonwealth pilots would have joined forces with the US (and USSR) rather than turning on their allies.
The USSR was certainly not an ally of Britain in 1940, Stalin had a pact with the Nazis you may recall. Even the USA was not an 'ally' as such, although the British Government appears to have promised not to let the RN ships to fall into the hands of the Germans. If the Nazis had the use of the German, Italian, French and British fleets the USA would probably acquiesced to what the Nazis desired, especially with the Japanese fleet facing the US in the Pacific. The axis controlled submarine fleets alone, in this scenario, could have created severe problems to US coastal traffic off the east coast and Caribbean judging by what many fewer German submarines caused in 1942.
Mike