And those people who claim to have been abducted and found themselves inside of one?
People who have worked with abductees and many of the abductees themselves have wondered if these so-called aliens were interdimensional and/or had a "paranormal" quality that endowed them with the ability, for example, to go through walls, doors, closed windows, and ceilings (among other things).
At the Westall School sighting in Australia, witnessed by over 100 people, including students, teachers, and farmers at a nearby market garden, the "disks" were said by some to be solid at times and to have an almost smokey quality at others (for example, when they moved through a stand of trees that stood too close together for such an object to pass through).
Imho the best book on the topic of “alien abduction” is John Mack’s final work:
https://www.amazon.com/Passport-Cosmos-John-Mack/dp/1907661816
He was a professional shrink who worked with abductees—and walks through a detailed discussion of lots of alternative explanations of what is happening.
This stuff is _very_ complicated...and the folks who claim to have easy answers are not asking the right questions.