I saw mine while on close-in sentry duty when I was in the Air Force back in the late 70’s. It was in Oklahoma and about 2 or 3 in the morning. It was clearly shield-shaped with a flat underside and had a dull but constant, reddish glow. I watched it move slowly across the sky from east to west, shield point forward, without a sound until it disappeared. It looked to be about the altitude of a commercial airliner but I couldn’t gauge the size at all.
I kept rubbing my eyes thinking I was just tired or seeing things, but it was still there. After it was gone, I called the tower and asked if they’d seen anything strange and they said they had not. I remember it all like it was yesterday.
There were a couple major UFO incidents up in the ICBM missile fields years ago. The Alert Response Teams testified they saw UFOs hovering over some of the Launch Facilities and crazy things happened to the weapon systems while they were observed.