Thanks. And actually, they do haha. The creators stated that dragons use magicka to fly as, at points, it is blatantly obvious that their wings can't sustain them due to their sheer size and shape. Though I could have misread. Additionally, in-game at least, they do use magicka to cast the thu'um (Which to be fair, is their only means of using magic) as if a heavy magicka draining poison, or the Staff of Magnus (After their magicka is completely drained) is used, they became unable to shout at you. Which is a tactic I often use in-game when fighting them.