I saw photos of a very similar flying saucer prototype, back in the 1980s, so it's likely to be a relaunched project that was shelved, just as the lifting body concept was. The horizontal spin motion gyroscope effect would likely give a flying saucer its stability, provided there's some controlled counter torque/rotation, as is currently applied to a quadcopter drone or helicopter. The big trouble with some single prop pushers is when you get to low speed near a stall and the plane wants to swap ends. The test pilots for the Lear Fan experienced this. I use to listen to their in-flight reports via an air-band radio while they conducted test flights at Stead , Nevada in the mid-1980s.