Both of those videos are very interesting. I didn't know there's so much documented data on UFOs.
Although I personally believe that life from elsewhere in the universe is very possible, there's still a chance that those UFOs originated from earth, and that other countries or even our own government has secret technology that even military officials don't know about. I've also heard theories that UFOs come from "aliens" who live deep underground, however I don't know if there is any scientific evidence to support that at all. But like Dr. Michio Kaku said, aliens could be millions of years more advanced than us, so they might not be limited by the laws of time and space like we are. And even if they were, if they had extremely long life-spans, millions of light-years might not be such a long time for them to travel anyways. There are infinite possibilities as to what they could be like and why (if) they're here.