[kleigenfreude]

> Sometime late in the 1960s, in the countryside of Vermont, my sister and I saw in the evening sky three round lights, apparently far-off, perfectly still and unchanging, each the size of a thumbnail held up before the eye. We hadn’t seen them appear—they were just there. They remained for a few moments, and then with instantaneous acceleration vanished over the horizon: in the blink, that is, of an eye.

Which was a jet that had been coming right at them that changed course 90 degrees. Probably the source of 99% of sightings if not more. Anything with three lights (white, red, green) or similar lights that appear to be "rotating" (because they blink, it causes the mind to come up with explanation of the blinking) is likely a human aircraft.

A sufficiently advanced alien civilization tends to fly without FAA-approved lighting.