Storm sorcerers have the Tempestuous Magic feature (XGtE, p. 52) at 1st level:
Starting at 1st level, you can use a bonus action on your turn to cause whirling gusts of elemental air to briefly surround you, immediately before or after you cast a spell of 1st level or higher. Doing so allows you to fly up to 10 feet without provoking opportunity attacks.
What happens when you move straight up ten feet?
- Do you stay up there until your next turn and fall or slowly descend?
- Do you immediately fall or descend?
- Can you use your next bonus action to climb another 10 feet by casting another spell?