Do Balrogs Have Wings?

[obloquy]

I don't think there's any written evidence that balrogs were--or Durin's Bane was particularly--gigantic. Greater than a man in size, for sure, and capable of flaring their silhouette to demoralizing effect, but not so large as to be unable (obviously) to make their way through the less spectacular doorways and hallways of Moria. Greater than Sauron in physical form? It seems unlikely. After a certain point, size becomes impractical for an intelligent creature, especially if we assume that, as Maiar, balrogs were probably accustomed to more comfortable dwellings than holes in mountains such as dragons made use of (note: Moria was not just a hole in a mountain).