You are absolutely correct. How people see things is often a manifestation of their own minds.
But that only raises the question: what was it they saw which was so outside of ordinary experience that their minds had to explain it to them with more familiar imagery?
In 1970, at Clark AFB, PI we were called out at 0300 fully armed to an alert. I was dropped off at the very extreme end of the runway where the runway dipped down and out of sight. I heard something mechanical just over the horizon and saw a shape rise slowly up over the hump where the runway dipped down. Bright lights, whining sound and a dramatic rising “up” about 75 yards from me. It slowly turned from right to my left after attaining about 100 feet altitude. It then roared and took off at an astonishing speed. I called the sector supervisor on my radio and told him I needed help ASAP. A Colonel from some other outfit came out and I reported to him what I saw, because I was terrified. He smiled and said “Sgt. You DID NOT see what you just described. Take tomorrow off and think about it.” I was allowed off the next day, and later that year, I saw a Harrier in Viet Nam. The incident described above was a test demonstration. I still have dreams about that night.