Before you dismiss the whole UAP\UFO please read the book by Leslie Kean on the matter. Over 700 accounts from all over the globe of unexplained aerial objects experienced by civilian airline and military pilots. A lot more have been explained away by wx balloons, Venus, etc. but there are credible instances that stir the imagination. Blue Book was a terrible cover up the US government did primarily to debunk the true sightings. The motivation was the Cold War: if unexplained aerial things were penetrating our airspace without our knowing it or control it would show our enemies our vulnerability.
Keep in mind BB is an American thing and these sightings have been recorded world wide by many people.
The book doesn’t purport that these are from out of our world or that they are manned at all. They’re just taking a scientific approach at the observations and coming to conclusions that on,y the facts support.