When a player is wearing a cape, the Elytra should adopt the texture of said cape, This is true until flying, in which it either dissapears or becomes blank. If the Cape is the Pancape, then it won't appear at all on an Elytra or become a blank Eltrya. When wearing the Minecon 2016 skin pack capes, they also won't have an Elytra texture and instead will have the default Elytra texture.

What should be happening: The Elytra should adopt the Cape's texture permanently while wearing the cape
What is happening right now: The texture either doesn't appear, makes the Elytra dissapear, or stays on for a bit, then dissapears or makes the Elytra not have a texture at all

How to Re-Create:
1.) Equip a Cape of any type
2.) Equip an Elytra
3.)
a.) [Founders Cape] Fly around a little bit then land. If it doesn't dissapear, then kepp flying and landing until it changes
b.) [Pancape] Wings shouldn't appear with it on at all or the Elytra won't have any texture at all
c.) [Minecon 2016 Skin Pack Cape Skins] Elytra shouldn't have a special texture at all

Just a note: If we have the Minecon 2016 Skin Pack, should we be getting the Capes at all or is that not a thing yet or ever. Just saying just in case this is a bug or not