People who support Ultraterrestrial Theory, such as authors Jacques Vallee and John Keel, point out that supernatural beings seemingly superior to humans have been reported throughout history. In previous eras they were called gods, angels, ogres, fairies, brownies, little people, demons, and more.
The Bible is filled with references to supernatural creatures, including giants, 'wheels' flying in the sky out of which incredible creatures emerge, and more. But references to flying disks were recorded centuries before the texts of the Bible. Cave drawing dating to 30,000 B.C. depict disks floating around in the sky, remarkably similar to modern UFO photographs.
This theory further states that species evolved on Earth along with homo sapiens, but are so superior it's almost impossible for us to comprehend their existence. All we know of them are fleeting glimpses of lights in the sky, occasional bizarre encounters between human beings and so-called aliens, and other unexplained phenomenon.