D&Dtools

You sprout a pair of insubstantial feathery or batlike (your choice) wings.
You can fly at a speed of 90 feet (60 feet if you're wearing medium or heavy armor).
You can ascend at half speed and descend at double speed.
You have a maneuverability of Good.
Using master air requires as much concentration as walking, so you can attack or cast spells normally.
You can charge but not run, and you cannot carry aloft more weight than your maximum load (see Carrying Capacity, page 141 of the Player's Handbook), plus any armor you wear.
Should the spell duration expire while you are still aloft, the magic fails slowly.
You drop 60 feet per round for 1d6 rounds.
If you reach the ground in that amount of time, you land safely.
If not, you fall the rest of the distance, taking falling damage of 1d6 per 10 feet of fall.
Since dispelling a spell effectively ends it, you also fall in this way if the master air spell is dispelled.
Focus: A wing feather from any bird or the wing bone of any bat.