They look like they use the Boxer motor off the old Ural motorcycle. Too bad the Yooks can’t borrow some Spitfires from the British to shoot them down.
As I was reading this thread, I was thinking about how this compared to Hitler's V1 attacks on London, then I read your post and realized I wasn't the only one thinking about that. Of course, the V1's were followed by the much more dangerous V2...
I was thinking something along the same lines. I have a home built ultralight airplane from the 1980s called a Skypup. Mine has a Rotax 277 which was originally designed for snowmobiles. It runs at a high RPM so it has a gearbox which reduces the speed to something suitable for a small propellor. I had so many great adventures in that little airplane.
My first thought was that the engines on the Shahed drones and the even cheaper decoys with foam airframes would likely be excellent powerplants for ultralight aircraft. With 3 gallons of gas, I could fly nearly a hundred miles with a low throttle setting.