Recently I spoke with a UFO researcher on the discipline of Ufology. He explained a bit about some of his cases: "plasma" was a big one. During our conversation I remembered my own personal story.
It was evening and the winter sky was dark -- with the exception of a sky field flicked with stars. I was walking along the street in a small city here in Ontario where the above is fresher and clearer than it is here in the big city, Toronto. Something made me look up. Above, way up, streaked a tiny burning bright. Immediately I discounted it being a satellite or meteorite: the speedy light zigged and zagged as if undertaking evasive maneuvers. The star-field relief gave my eyes some 'registration'; a reference point for the non-static light to play against, confirming to me that what I was seeing might have been piloted by an indecisive, albeit quick-thinking, navigator.
The Ufologist nodded. He looked as though he believed that I had seen something not of this Earth. I'm not sure I believe it. But that's my UFO story.