From Pathfinder Book of the Dead, which isn't enabled.

Ghost Flight

FEAT 8

Activity 2 actions

Archetype Ghost

Frequency once per day

You can suppress your tether to the ground, overcoming your resistance to fly free. For 10 minutes, your fly Speed doesn't restrict you to only a few inches off the ground, allowing you to travel to any height you choose.

Pathfinder Book of the DeadOGL