Quote Originally Posted by Rhapsody
Get all episode completes, but dont go to Zanarkand last, because to get it, you need to automatically return to the airship.
And then Brother gives you it in a cut scene. You don't need to search the airship for it.

And for added confirmation, I'll just say this again. you have to complete Bevelle and everything else.

I was pretty sure that you could talk to Maechen (standing off to the left) to return to the airship automatically after getting Episode Complete. But I didn't take the risk of completing Zanarkand last either.