Actually, with a totally different history from a PoD before WWI, it might be possible. Germany wins WWI (OK, not easy, but possible). Spends the next decades building up the Glorious German Reich on the backs of the conquered French, and using much of Central Europe as its colonies, in a way.
Meanwhile, the UK has the same massive debt problems as OTL (as France has no chance of paying anything back).
The US stays in Splendid Isolation (probably a pre-condition for Germany to win).
So, when Britain gets stroppy about the Reich taking over all of France's colonies in the '40s, Germany manoeuvres them into war, and with crushing military superiority in Army and Air Force, they invade Britain using their superior air power to counter act the marginally superior RN. It goes much worse than the High Command expects (all those torpedo bombers and dive bombers aren't quite as effective as they'd hoped, and the RN's better trained than the Imperial Marine, but ....
It's doable. But you need a WWI PoD or earlier.
Of course, this wouldn't be anything like OUR WWII, but it could be A WWII.
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Oh. And you need to remember to start your invasion by landing on the Isle of Thanet
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As others have said. If it's 'our WWII', no. Nope. Ain't gunna happen.