I too have wondered if real wings were meant, or if the
Balrog used his own power over fear, fire, and darkness to create them. I see no significant difference, like Ciryahir said, and I don't believe
Tolkien intended us to believe the creature could fly anyway. Real or percieved wings, I have no real opinion. There are a number of very obvious reasons why it may not have been able to fly out of the chasm(assuming it had actual capacity for flight), not the least of which is that it had
Gandalf heading down as well, and Gandalf would have been clinging (especially if the Balrog might fly)and perhaps hewing with his
sword as well. Flying up would have brought Gandalf up. But I don't believe we are intended to think there was a chance of that happening anyway.
I have seen a thread for discussion of the paths of the dead in some forum here. An arguement in there was quite the same. Tolkien said exactly what he meant, and was very good at doing it with few words.
Also, Gothmog you told ReadWryt in your last post that the confusion doesn't come from the author. I think that's exactly what ReadWryt was trying to say in his previous posts.
Picture the
demon from the movie "Legend", with a slightly less human face simply because it looks more
evil, add glowing white or red eyes, make it black as charcoal, bigger, with some long, straight unkempt looking black hair, black wings like a bat, and rippled with muscle. My Balrog.