I did a quick search, and i cant find anything about using this item in instances, only for exploration.
With Aviana's Feather, the reward from Aviana's Request - Quest - World of Warcraft you can fly straight to the final boss or anywhere in the dungeon.
I'm sure you are not supposed to use it in instances but its a great way to get to the final boss and more in skyreach so you can farm it, with possibilities for other dungeons.
Its a fairly simple item to get for anyone with an Inn to get.
Some Screenshots:
Feather skyreach - Imgur