Backlytra Mod for Minecraft 1.9/1.8.9 backports Elytra from Minecraft 1.9.2 to Minecraft 1.8.9, 1.7.10, and 1.9. Supports vanilla resource packs to override texture and sound, works with capes, has Quark-style dyeing, everything. Craftable by default, can be configured.
Download link: Backlytra Mod for Minecraft 1.9/1.8.9