I am quite certain that I read somewhere that RAF ace Robert Stanford-Tuck had a .32 Beretta, but have no idea whether it was captured from the Italians or was something that he bought before the war began.
In, "Lancaster Target", the author mentioned that some of his pals playing a practical joke on another crew member found themselves facing a heavy automatc pistol when they forced open his door. But he didn't say which actual model or make the gun was.
Air Vice Marshal J.E. Johnson said that he was amused by the sort of pilot who checked his survival gear: compass, map, revolver, etc. before each flight. He preferred to think aggressively, and presume that he wouldn't be shot down, and need that gear. But he obviously saw it in use. He ended the war with 38 kills.
I've seen a photo of RAF pilots in North Africa with six-inch .38 M&P's in holsters meant for guns with five-inch barrels. The butts stuck way out.
Another reference mentioned that among the guns carried by Indian Air Force pilots were some Colt M-1917's. Must have been Lend-Lease. Wish I could recall which book it was. I think one about Spitfires.
People being what they are, bartering with infantry troops probably got some enemy sidearms into Allied hands, and the reverse.
Photo of Erich Hartmann show him wearing a typical .32 auto. Don't know what, probably the PP. But he was once told to leave his weapon and belt outside a room where he was going to meet Hitler, who was awarding him the diamonds or the swords (can't recall which) to his Knight's Cross. Hartmenn said that he would leave rather than be told that he couldn't be trusted to meet his Chancellor with his gun. Told this, Hitler rescinded the order and ignored his gun. Hartmann, the top scoring fighter pilot of all time, got his award. He had 352 kills at war's end. His crew chief was given a pistol by Hartmann that looked about like the one that Hartmann also carried. But it was holstered in tha photo that I saw.
T-Star