Flight

You gain controlled Flight up to your speed. If you take damage while flying, your altitude drops by 20ft. If this would reduce your altitude to the point where you touch the ground, you become rooted and cannot fly again until the end of your next turn. If the attack that reduced your HP came from a flying creature other than yourself, you do not lose altitude.

When you end any movement within 5ft of the ground, Flight ends (Causing you to become rooted if this was cause of damage taken).