Who knows? A lot of weird stuff has happened over the years including the killings in that Alaska town that went abandoned after a monster attacked several people. Only problem is lack of physical evidence to back it up. It may be something misidentified?
UFO's I do believe in because I've seen them with my own eyes. No aliens though!
I'd probably be a believer in aliens before I would a bigfoot. We can't be alone in so much that hasn't been discovered in space. These lores & theories all come down to evidence.
There's just so much we don't understand about the universe and there is life out there. The question is are the objects seen in the air and water of earth origin or not? It may even be from parallel dimensions. Just too much to figure out in our lifetimes most likely!