Dragonflight

As seen in

A Throne Built On Stars

Physically, dragons should not be able to fly. But they do.
They can soar, dive, and hover as their massive wings beat the air and twist as they reproduce while flying. All of these things should not be possible. So how do they do it? Do they have hollow bones and massively multilayered muscles? Is it magic?
Their bones are not hollow, in fact. But they do have muscles that are unique to their species and sub-species. You see, their muscle fibers are made from an incredible material. Let me explain. The muscles in your arm are made of a flesh-like substance, correct? Dragon muscles are enhanced with a sinewy black element. (While wise, the dragons willing to share their knowledge with Torhal Ardonatto knew nothing of their physiology beyond their basic needs.)
The long strands of this mysterious black element lie atop each other, but not at all aligned. Instead, they are staggered slightly. It has been hypothesized by dragonologists that this alignment pattern prevents tearing when they lift themselves into the sky. So according to the theory, dragons are able to fly because their muscles are enhanced.
The only way to test this theory would be to examine a dragon's body after death. Thus far, this has not been possible. From the limited sharing of information between Torhal Ardonatto and the dragons willing to speak to him, it is understood that such an investigation would be perceived by dragon-kind as an insult.
There does exist, however, an account of a man who came across a dragon's body where it had fallen from the sky after being killed by a rival male. The account does share, in fine detail, what the man saw in the dragon's wounds. While the man did not poke and examine the body in any great detail, it is through his observations that we know about these mysterious black filaments in dragon musculature at all.
So in conclusion, Dear Reader, while dragons should not be able to fly according to how we understand physiology...they can and do. And they do it well.
Find out more about dragonkind in On Dragons: A Book by Torhal Ardonatto