I have seen one also and the mesmerizing effect won’t let you stop looking at it.
My wife and I saw one on our honeymoon in ‘04. We were traveling across the high desert in SW Wyoming. It was in the middle of the afternoon, in broad daylight. I will preface this with the fact that I have been a pilot for over 35 years I can tell, for incidence, the difference between an F-15 and an F-16 at 3 miles. I also hold a Masters in Electrical Engineering and a BS in Aeronautical Engineering. Needless to say, I’m pretty familiar with technology and aircraft.
What we saw looked like a hot air balloon that had been compressed vertically, iow, a thick, saucer like shape with blunt edges and lights on a cylindrical structure on the bottom. It was moving right to left across a small valley at about 500’ agl at what I would estimate was about 300 knots (jet speed). We were on a small rise and I saw the shadow of whatever it was on the ground moving with it plain as day. It made no sound whatsoever. Here’s the really weird part. We were way out in the middle of nowhere. I could have stopped in the middle of the road and not seen another car for hours. We had 3 cameras on the front seat of the truck between us, two still cameras and a video camera. It was about 30 minutes later before either one of us acknowledged that we’d seen anything and another hour before either one of us actually realized what we had seen. Very odd because my wife and I both took hundreds of pictures on that month-long, 10,000 mile trip. I don’t know what it was or where it was from, but if it was ours the gubmint has done one hell of a job keeping the technology a secret.