My grandmother saw a craft of some kind, I believe this was in the late sixties. She was an intelligent and very rational person, and was accompanied by my uncle at the time, they both saw and recalled the same thing, so I don't think they were mistaken. Back in the last century living in a rural community, there was not much desire to talk about such things, so they stayed quiet for many years.
When we were talking about the moon landing and rockets etc once, she mentioned that she had seen one of the Russian ships, but sometime later she told me she now didn't think it was Russian at all, and finally gave me more details. Driving on a country road they saw a craft land in the field beside them. They can't recall if the car stopped running or if my uncle parked it. There was a classic saucer shaped craft, with port holes in it, and they believed there were people visible looking out. They both recalled that it was exceptionally silent at the time. The craft flew off in the direction of a remote harbor area which has been the subject of many sightings over the years, a favorite area of author Bruce Cathie. We also discovered later that the farmer who owned that piece of land had called investigators in to look at a burned circular patch in his field.
I have never seen anything I consider unexplained or unidentifiable myself, but I don't know what to make of my grandmother's recollection of an encounter with a vehicle she was pretty damned sure nobody was supposed to have at the time. I'm also not inclined to blame 'aliens' for anything odd which may be seen flying about in our skies, that is an awfully big jump to make from 'not a technology I believe humans have right now'.