[Berosus]

I’ll check. Perhaps airplanes were used.

[SunkenCiv]

It's possible, there was a 1930s German design that worked, but was never produced in quantity, and was destroyed apparently to keep it out of Russia's hands. The Sikorsky (naturalized American, born in Kiev in the Ukraine) design wasn't manufactured until 1942, and choppers were never used widely in militaries until the Korean War, AFAIK.