Just a random thought – Pretty much all alien movies show alien ships piloted by alien beings of some sort, while the most likely scenario would not include any “manned” craft at all. Why would aliens even bother to make the trip, even if they had some kind of faster-than-light travel capability? We certainly don’t do that kind of thing. We send robots out into space and land them on the surface of other planets all the time.
If I think back to all the UFO stories I’ve ever heard, from the 1950s to today, the behavior of these UFOs seems rather stiff… fly in straight lines, follow alongside airplanes matching velocity perfectly, make zigzag moves and hairpin turns that would generate so much inertia that the momentum of the “stuff” inside an organic alien body would liquefy… all this behavior speaks to computerized AIs, not to ships piloted by organic beings. With their obviously superior technology, I’m 100% certain the only alien craft humanity would ever encounter would be a physical AI construct… an entirely artificial life form. The ships themselves would not be transportation for the AIs, but literally be the AI beings. Just like us meat sacks walk around in our bodies, the AIs would fly around space in their exotic nano-metal alloy skins… kinda like Flight of the Navigator… only without the squishy human child inside. There would probably be zero room for anything besides scientific sample collections.
The truly scary thing would be fighting some kind of war or conflict, or fending off alien planet-scavengers. Likely, they would do what our military is already trying to do… setup a drone force of remote controlled and fully autonomous robots that can pulverize a kill zone before a single “friendly” human being sets foot there. Why wouldn’t any intelligent alien being not do exactly the same? It would be a fight we absolutely could not win. Heck, we can’t even effectively defend against an incoming asteroid these days… all the aliens would have to do would be to literally throw some rocks at us and we’d be defenseless.