Let's start with the acronym, UFO. That means Unidentified Flying Object. I see them every day. At 35 thousand feet, I don't know it they are a 737 or an Air Bus 360. They could be from the planet Vulcan... I don't have a clue. I guess that makes them UFOs
I do recall John Glenn's first orbital flight back in 1962. He reported seeing all these little 'gizmos" swirling around his window. Even laughing about them. Turns out, they were just part of the debris left over from the final stage separation when he went into orbit. They orbited with him.
The entire UFO thing drives me nuts. If they have the ability to travel many light years to get here;
1. Why have they never said hello?
2. How come we have never heard them on the electromagnetic spectrum (i.e. radio) --- And we have spent many millions of dollars listening for them hearing cosmos static hundreds and even thousands of light years in the past, and haven't heard a single peep of intelligent transmission even with networks of millions of computers analyzing those signals.
Kind of scary there that we might be alone in the local universe or at minimum, we're the first that has figured out how to broadcast in the electromagnetic spectrum.
Sorry, but I really get aggravated with the UFO crap. There is not a single shred of hard evidence to support that we have ever had a visitor. The hustlers who push it are just cashing in on the gullible.