Put down a repeating command block, and type in the command:
"/tp <Username> ~0 ~0.1 ~0"
after powering it, start gliding with the elytra.
After a some seconds, you will go back to your position a few seconds ago, but higher. Considering how amazing the elytra is, I've tried to make it so you are teleported up so you can fly forever with an unbreakable elytra.

I hope that this can be fixed with the next snapshot!