Falling from a large height doesn't open elytra, no matter how far the fall is. The elytra don't open in survival, creative, or adventure mode. This has led to many deaths because I jumped expecting to glide.
Related issues
Attachments
Comments
migrated
[media]
CubeTheThird
You have to jump mid-air to activate it.
migrated
Oh, that seems like an odd thing to not include in update notes on Mojang's website :/
Sorry for the false bug report.