The avatar began free-falling toward the ground.
It was much faster than normal, and the secret behind this was the use of telekinesis.
He used telekinesis to eliminate air resistance.
By tearing apart the air in the direction of his fall, creating a temporary vacuum, he was able to fully embrace the force of gravity.
By the time he had fallen about halfway,
Swoosh!
He used teleportation to move closer to the World Tree’s trunk.