I did hear a stereotypically UFO hovering sound a few minutes later even though there was nothing anywhere around me.
Either this is psychological and people have some kind of built-in hallucination effect for this specific phenomena in the sky. Which is interesting and should be studied. Or it's the real thing. And if it's real it's not going to affect our life by any amount unless we want it to. If the aliens wanted to land and share information or anything else with us they would have done it already, and we can't force them to do any such thing so who cares.
I am also extremely skeptical of Roswell type claims of crashed craft, unless the aliens have horrible QA engineers or we get millions of visitors per century I doubt they would crash one of their flying cars on our planet.