I haven't, and I don't believe anyone else has either :)
Those were errors of perception, fantasies, etc.
At worst—elves or some such creatures :D:D
By the way, there was one interesting study on UFO descriptions; it compared them with descriptions of encounters with elves and other magical folk in folklore and medieval texts and... they were amazed. The similarity was striking—to the point that in medieval texts, before the appearance of own unholy forces, horses traveling along the road would stop, become frightened, and flatly refuse to move further, while in UFO descriptions, cars would break down and fail as they approached.
So if any such phenomena did exist, I'm more likely to believe that people saw spirits, elves, or unholy forces, which—due to their mindset—they perceived as aliens (in a high-tech style).