Had a neighbor here when I moved out. He was a engineer for the Apache plant down there.
Told me that the kids were outside and called he and his wife out when it came over. Said he could look directly this way and that way and estimated it to be at least two football fields wide-real low. Told me that all he was thinking was, “What the hell do they have driving that thing?” It was completely silent. The lights underneath were the propulsion system-he figured.
The key words are-”do they have” I think he knew.
He passed away a few years ago and his wife sold the place as it was a get-a-way for them.
Interesting! Most likely anti-gravity propulsion.