This is interesting. I have read some Bible scholars who postulate that anything ET is demonic, period. OTOH, isn't it possible that God in his magnificent wisdom might have created other races in other places? Perhaps some of them didn't suffer a "FALL" and remain in a right relationship with the Lord of all creation? Then of course there is that race of the Angelic Host.
I do believe that SOME UFO phenomena [less than 1%?] may be angelic forces.
I know some are convinced that EZEK's chariot was a UFO and that Christ ascended in a cloud created by a UFO that then took Him away.
Personally, I don't think God needs UFO's at all. BUT, HE MAY CHOOSE, on occasion, to use them as He might see fit for whatever reasons.
One of my friends who's had a very strong relationship with Jesus since toddlerhood, asserts that she'd known most of her life that there was evil on other planets. Certainly we know that
ALL
CREATION
GROANS EXPECTANTLY for the manifestation of the sons of God.
Why wouldn't all creation be keenly interested in their future rulers who will "reign with Christ" throughout endless ages and endless galaxies. Earth is evidently bootcamp for training said rulers to rule based on an economy of Agape Love, The Golden Rule etc.
I do NOT believe that ALL UFO craft are 'merely demons materializing as craft.' I don't see A demon or even a legion of demons pulling off the huge mother ship thing at all. But I can easily believe that various ET races have been drawn into satan's deception and games. And, I can believe that SOME ET's are bioengineered bodies housing demons.
God only really knows.
imho.