Although End ships appear to have both a mast and boom like a sailboat, they don't have sails. The end ship is the only way you can obtain a dragon head or elytra in survival mode.

Where is elytra in end ship?

The treasure room, where a shulker guards the elytra.

Can elytra only be found in ships?

/ˈɛl ɪ trə/ ᴇʟ-i-trə) are rare wings found in end ships that are the only single-item source of flight in Survival mode.