When using elytra you just fall and only sometimes you glide and I know this is not intended behaviour but hopefully it can be fixed thanks Mojang!
How to reproduce: Fly up in creative or build up or get in the air somehow in any gamemode (except spectator) and then try to fly as you usually would but you just fall and in survival / adventure you take damage instead of gliding It happens in 1.10 + up to 1.11 snapshots