Helicopter?

https://www.youtube.com/watch?v=xtt-OgLNGqs
https://en.wikipedia.org/wiki/Flettner_Fl_265
https://en.wikipedia.org/wiki/Focke-Wulf_Fw_61
https://en.wikipedia.org/wiki/Flettner_Fl_282
The helicopter in Where Eagles Dare is actually a post war US made Bell 47 but yes, the Germans did have helicopters in WW2 and as the film footage shows even before WW2.

Trust me. I know what I'm doing.

Thought the same lol

There was a Hitchcock movie from the 1930s that had a helicopter in it. It wasn't a real helicopter in the film, but a miniature. Still, they did exit back then, apparently.

The first production line helicopter was the American https://en.wikipedia.org/wiki/Sikorsky_R-4, in 1942, with it going into service January 1943. So not so long after the US joined WWII, helicopters were being mass-produced already, with experimental version in the 30's, as mentioned by Hotrodder.

This fact would've been very easy to research Ray, instead of displaying your ignorance to the world.