For one thing it was detected (according to the unclassified releases) as high as 80,000 feet AGL. There's no design of any type right now that can fly at 80,0

For one thing it was detected (according to the unclassified releases) as high as 80,000 feet AGL. There's no design of any type right now that can fly at 80,000 feet AND hover at low altitude, all without airfoils. That is also without accounting for the extremely high-G turns with no airfoils. If it had been some kind of nuclear ramjet (which wouldn't work at low speeds) there would have been a visible plume of hot gas. There wasn't.