I watch “Ancient Aliens” and I heard the same argument, about how angels are actually misidentified aliens, and that they bred with humans to produce giants like Goliath. The Bible verse they’re talking about is:
“And it came to pass, when men began to multiply on the face of the earth, and daughters were born unto them, That the sons of God saw the daughters of men that they were fair; and they took them wives of all which they chose. …There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown,” Genesis 6:1-2,4
It makes it sound like these “sons of God” could be something other than human men, but Adam was called the a son of God (Luke 3:38), Paul called us “sons of God” (Romans 8:14), and John identified as a son of God (1 John 3:2) .
I think that, like every interpretation of the Bible, translation has a lot to do with it. Nephilim was rendered as “fallen”, but could also have been “feller” which meant tyrant or bully. Also, Nephilim was written as “gegantes” in Greek, which looks an aweful lot like giants, but would have been “Titan” in translation. (resource). I have do do some more looking into it, but when I hear talk of giants I always think of really big intimidating people (like the Vikings), and that would have fit with the bully/tyrant translation.
I like the show (and the topic) just because it makes me study my bible more, but I can’t say I actually think Angels are the kind of aliens that fly around in UFO’s (though, I s’pose they could be considered alien, since they aren’t of this world?).