Do you think aliens in ufos have visited Earth? (And all things UFO)

DaveXA said
Well, he didn't exactly say aliens. And we all know UFOs can mean a lot of things, so, I'm not so sure any of that is exactly earth shattering.

It was more like a non-answer answer. Also, why can't he answer the questions he was asked there in a public setting? What is stopping him?