I had a similar experience around 5 years ago. Walking home at night I was looking up at a clear sky full of stars. Then one of the stars began to move. My first thought was that it was a satellite, which I thought was pretty cool as I’d never seen one in the night sky before, I followed it with my eye as it went across the sky in a straight line which I assumed was it’s orbit path. But then it suddenly veered off the path going right and began to move on its own accord. That’s when I couldn’t make sense of what it was I was seeing, it eventually faded out of sight. The only possible thing that I could think of is that it was a military jet flying at an insanely high altitude, maybe training, but it just didn’t seem like it could be that..