Villager Trade

First type

/summon Villager ~ ~ ~ {Profession:1,CustomName:"Elytra"}

Afterwards, stand in the villager and run all of these commands:

/entitydata @e[r=4] {CustomNameVisible:1,Career:1,CareerLevel:42}

/entitydata @e[r=4] {CanPickUpLoot:0,PersistenceRequired:1,Invulnerable:1}

/entitydata @e[r=4] {Attributes:[{Name:"generic.knockbackResistance",Base:"1f"}]}

/entitydata @e[r=4] {Offers:{Recipes:[{buy:{id:diamond,Count:52},sell:{id:elytra,Count:1}}]}}

/entitydata @e[r=4] {MaxUses:99999999}