It's not WW2, but awhile back I acquired a 1968 MA-1 on eBay with a brown leather nameplate bearing Naval Flight Officer wings and the simple inscription "Marcia Ann" beneath the wings. There was a serviceman's name stamped at the inner collar area in black ink, so I did some Googling and ultimately discovered that an individual of that name was indeed a Navy Radar Intercept Officer during the era in which the jacket was likely issued. I emailed the gentleman and got a very friendly and detailed response indicating that he believed the jacket was issued at some phase of his training, but ultimately turned in for a "WEP" of proper Navy specification. He had no idea where the "Marcia Ann" inscription came from, but he was confident the jacket itself was issued to him.
There may well have been a scenario under which a Navy man was assigned to an AAF unit for training or some other purpose and was issued an Army flight jacket. Alternatively, the jacket could have been acquired privately after the war and the nameplate affixed by an owner who was perhaps not so particular as we . . .