Remember, many of the UFO/UAP "shapes" have changed over the years. From the late '40s it was the "flying saucer" based on the Kenneth Arnold sighting (bold by me):
External Quote:
This was the first post-
World War II sighting in the United States that garnered nationwide news coverage and is credited with being the first of the modern era of
UFO sightings, including numerous reported sightings over the next two to three weeks.
Arnold's description of the objects also led to
the press quickly coining the terms flying saucer and flying disc as popular descriptive terms for UFOs
https://en.wikipedia.org/wiki/Kenneth_Arnold_UFO_sighting
This continued through the "80s with popular hoaxes like the Gulf Breez photos using the flying saucer:
Starting in the '80s and into '90s the "black triangle" became popular (bold by me):
External Quote:
During the early 1980s several hundred people claimed to have witnessed UFOs flying over, or near to, the
Hudson River in New York state. These sightings involved hovering or
slowly-flying, V-shaped objects rimmed with colorful lights.
External Quote:
The Belgian UFO wave began in November 1989. The events of 29 November were documented by over thirty different groups of witnesses, and three separate groups of police officers. All of the reports related a large object flying at low altitude. The craft was of a flat, triangular shape, with lights underneath.
External Quote:
A widely reported appearance(s) of
black triangles involved the "Phoenix Lights" events, during which multiple unidentified objects were observed near
Phoenix, Arizona and videotaped by both the local media and residents beginning on Thursday, March 13, 1997.
https://en.wikipedia.org/wiki/Black_triangle_(UFO)
These days, it's the Tic Tak, which is just a way of saying an indistinct blob that is wider than it is tall. That's only since the release of the Navy videos in 2015, though I'm not sure when the phrase was actually coined:
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Underwood recorded the FLIR video, and coined the description "Tic Tac" to describe the infrared image, but did not himself see any unusual object.
[9]
https://en.wikipedia.org/wiki/Pentagon_UFO_videos
After each initial sightings, lots more followed seeing the same shape as each new shape became popular.
I'm just suggesting that the "shapes" of UFO/UAP are as much a part of the popular zietgeist as much as any actual observations.