player will jump off of 5 block or above cliff and wings will not activate player will then land take fall damage. occasionally wings will activate after ~10 blocks and will glide relay fast and then take no fall damage and when landing on ground will be able to jump up 4 blocks in the air.
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[media]

jump in mid air to activate a elytra
the 4 blocks in the air is just perfect timing with knockback upwards