And old assumption, widely held until the soviet Bear bombers shattered the misconception that propellers must remain subsonic.

https://en.wikipedia.org/wiki/Tupolev_Tu-95

Or the appropriately named Thunderscreech.

https://en.wikipedia.org/wiki/Republic_XF-84H_Thunderscreech

Ya, three years after the bear. Call it an experimental fighter, but it was sputnik-style catchup. It was US designers saying WTF is that? They needed to figure out what the bear was capable of, so they needed to study supersonic propellers asagdp.

Fans are pretty much like propellers and the F15 uses a turbofan and goes supersonic. It works by inlets and exhaust nozzles that slow the air the speed it up again. The only reason that might not work on an electric drone with fans and nozzles is not enough power.

Yes, it is why last iteration by Luke Maximo & Father used trimmed-down propellers rotating really fast :-)

They should look at Prantle Wing (also applies to propellers) to get more efficiency out of the design.