I'm pretty confused about that myself; from the rumors in the afterworld I suspect that it's not actually possible to get to the roc's nest, but the roc still seems like it has a purpose. My guess is that I want to use it to fly over the labyrinth so I can avoid the minotaur, but the last chance I get to drop off puts me in the north end of the village, which is not terribly helpful. Plus, if the cottage and jeweler's characters are right I need to get into the jeweler's shop before returning to the cottage, but I haven't made any progress on how to do that.
Perhaps I've missed something? I've got the sword and shield and made the marlin but I have not done anything I don't need to do to accomplish those two goals. Oh yes, I've also got the labyrinth expert to admit that you can't defeat the minotaur.