I've always told my kids that IF an alien ship arrives in their lifetime here on Earth to be afraid. Some will think I'm a dick for doing that, but I think there's reason to feel that way.
IF we were to encounter another planet with less-developed life right now, what would happen is we would fly down and eventually take the planet as our own. Why? Because of its value. Just like we saw with the colonization of America. It's not a question of how it would go, but rather whether we would, as a species, be able to control our greed. And I think the answer is we would not control our greed, because we as a species never have.
And why am I so sure that an alien species would be sort of assholes like us? Because intelligence is a byproduct of hunting and killing to live. You have to think in order to survive as a hunter. You don't have to think in order to survive as a leaf eater. So if we are blessed enough to encounter another species (I say blessed because time is the issue, namely whether two species happen to exist at the same moment in vast oceans of time), there's a good chance things will start well and end badly, sort of like the Americas. History is a good teacher there IMO.
Now I'll admit that there might be that evolved level of society that we haven't sniffed yet, where we master not only the technologies but also the social side to become something different than we have been. So if there are visitors who aren't taking over Earth, that means they are probably one of two things...
1. Extremely highly evolved. This would be a really good sign too btw, not only for us not becoming dinner or slaves, but because then there is hope that we also might get there and maybe they'll help us out at some point.
2. Higher dimensional beings. This removes them from the behaviors I would associate with a predatory species who develops enough technology to travel the stars and enough cultural advances to avoid killing themselves with said technology.
Went on a bit of a run there I realize. But it's something I think about lol. Oh and here's another article on the San Diego incidents as well as on the Navy's approach to this and some other stuff. People say "where is the proof?" Well those fighter incidents are pretty fucking good proof IMO.
It was in HISTORY’s series 'Unidentified' that the active‑duty Navy pilots who encountered the crafts first came forward to share their stories.
www.history.com