I saw the Black Triangle UFO [1] in Duluth, MN about 10 years go. It went from a low altitude hover to a slow glide across the night sky. I was standing almost directly under it in a parking lot. I thought it was a strange pattern of new streetlights for a few moments until it started gliding. Always wondered what that was.
[1]: https://en.wikipedia.org/wiki/Black_triangle_(UFO)