Most haven’t seen one yet many have. I saw one in 1973 in Holly Springs Mississippi in daylight. There was UFO 200 yards ahead of us, I was in the car with a friend. The aircraft was approximately 50 yards wide and 100 feet above the tree line. It was dark black but metallic looking. When our car got to within 100 feet of the UFO on this two lane highway it out of nowhere took off into the upper atmosphere. I mean it must have climbed 50,000Ft in seconds. I remember it like it was yesterday.
No doubt in my mind about the existence of Aliens and beings from other worlds, although I can understand the skeptics. It would be hard for me to believe if I never saw one. Just remember that just because we cannot master the vast oceans of space and complete interplanetary space travel yet does not mean others from other worlds who have been around much longer could have more advancements in technology and science than we could imagine.