https://www.newdawnmagazine.com/articles/what-are-ufos-terrestrial-extraterrestrial-metaterrestrial-theories
" The UFO phenomenon appears to be multifaceted and there is no neat, simple answer to what it’s all about. In my judgment, the public and even many Ufologists are indiscriminately lumping together UFO sightings and incidents into a single phenomenon. But the evidence indicates that no single explanation can cover all the experiences and events brought together under the label “UFO experience.” It is a multilevelled phenomenon. And each level – terrestrial, extraterrestrial and metaterrestrial – is qualitatively different from the others. Each has its own unique forms of UFOs, and each form has to be distinguished from the others of that level."