[Trump_the_Evil_Left]

Though of course there may be many mysteries through millennia from visions, seizures, dreams, etc. but I don’t think people were having all the specific “recollections” of being abducted and probed by space aliens until there was a body of Sci Fi works and movies to draw upon in recent decades.

[LadyDoc]

You are correct. In the past people were not abducted by UFOs.
However, people who disappeared and came back dazed and confused did occur. It was assumed they were kidnapped by elves, or demons etc.

[exDemMom]

There is a fairly common sleep disorder called sleep paralysis that can cause people to have very intense hallucinations. I believe that in ages past, the hallucinations were of supernatural phenomena, but as we moved into the space age, those hallucinations shifted to reflect more science fictiony themes.

Sleep paralysis runs in my family.