You know, if aliens are really out there, they'd probably classify Earth as natural reserve, where they would have biologists and anthropologists come down, from time and time, to study the formation of a civilization. Perhaps with the aim of expanding their knowledge of their own culture.
There are more UFO observations during wars or natural disasters, probably because there are more things to observe during time of great change. Like how human journalists flock to battlezones and how volcanologists to volcanos.
As for abductions, I don't think this happens deliberately. If there was a time when aliens abducted humans for experimentation, by now they probably have done all the experimentation they needed, like thousands of years ago. Though from time to time, humans might get caught as bycatch, when the aliens are trying to scoop up something else.
Other than that, I think the UFOs in most videos are rotating, simply because it's got only one sensor that can only scan in one direction, so they rotated the whole thing to do a sensor sweep.
Btw here's photo I caught.... of my own saucer multicopter
I actually found this game while searching for UFO photos to base it on.