When flying in an Elytra at speeds faster than possible without using commands, you suddenly lose all your velocity.

To re-create:
1. Give yourself at least speed 3. Speed 5 is the best to experience this.
2. Build a tower and get to a Y axis of at least 120 over the average surrounding terrain.
3. Jump off, and after a few seconds dive 50 blocks and then re-stabilize
4. Wait a few seconds until you lose velocity.
5. SCREAM IN ANGER!!!