Actually, the Bible never says what type of life form God is or what the angels or demons are. They just are, and they're from the heavens. They created us, but the Bible doesn't give us in depth details about how they did that either. All we know about our creator is what he and his angles want of us and what they can do.
In the book of Ezekiel, the angles are seen standing around a wheel within a wheel, and that "flaming chariot" didn't know which way it went (It had no face or eyes like a horse and chariot). It was also a silver color, burl (sp).
John 4:24 "God is spirit,..."
Agreed on some of the visions of angels and demons though! Sounds a lot like UFOs. Although their are some today that claim that UFOs aren't aliens - but angels and demons!
Can't say as I've never seen one - yet. Although I spent two weeks of nights working alone outside on an abandoned Air Force base in the Mohave Desert. Lots of quiet down time to stare and the stars. I kind of figured if I was ever going to see one - that would have been it!