You're right. Doesn't Revelation describe angels in heaven as having six wings, and also covering their faces with their wings? I can't remember offhand. I guess I've never thought much about that.

Angel simply means messenger, so it's hard to say.

Isaiah 6:2 " Above it stood the seraphims: each one had six wings; with twain he covered his face, and with twain he covered his feet, and with twain he did fly. "

"The revelation given to Isaiah was of the King, the Lord of hosts, a being greater than any earthly potentate. He was seated on a throne, high and lifted up, with bright-winged seraphim on either side as a royal guard. "Each one had six wings; with twain he covered his face, and with twain he covered his feet [in token of reverence and humility], and with twain he did fly," representing an instant execution of the Lord's bidding. Heavenly beings stood around the throne of Omnipotence, waiting His commands, and swift in the performance of their service to the inhabitants of earth." {BEcho, September 9, 1895 par. 8}