A simple client side mod.
Whenever you are in the air, if you have an elytra in your inventory, it will automatically swap your chestplate to your elytra. It will remember the last chestplate you were wearing, so it will automatically equip the last chestplate you had. As for elytras go, it will prioritize highest durability. It will not equip an elytra cursed with Binding.
Also, while gliding with an elytra, you can tap your Jump key again to cancel your flight. It will swap to your chestplate if there is a valid one.
