The term UFO just means we don’t know what it is.
I recall when the Harrier jet was first released some were spotted without any markings many UFO reports came in.
They were spotted over some larger towns to let people know hey look what we invented.
Probably a lot of sightings were like that.
But when hundreds of people, say, in the Phoenix area report that they saw a huge boomerang-shaped thing that blocked out much of the sky and stars, I have to wonder beyond the conventional and can’t accept the ‘official’ explanations that just don’t fit the behavior of the thing.