Pipit finds some of the things Link tells him impossible, and from anyone else, he would dismiss them outright. But Link always has the most guileless, earnest look on his face, and Pipit can do nothing but believe him.
As it is, he sees little enough of Link anymore, and there is no reason to taint what time they do have together with skepticism and disbelief.
It is perfectly proper, of course. Link has an important task to accomplish, and as much as Pipit wishes to help him-- legends are legends, and he supposes they must be obeyed. There is no legend that speaks of another young man with an affinity for birds, aiding the first, and so Pipit remains on Skyloft, preparing to be the best knight he can be. That is the way for him to help.
But still. He keeps and extra watch out, every night, by those mysterious pillars Link uses, circling on his Loftwing, straining to see what lies below. He sees patches of green, sometimes, but nothing more.
There is no way to tell when Link will return, these days. He appears without warning, and the townspeople will find him unexpectedly, sparring with the master or browsing through the bazaar.
But whenever he does return, no matter how weary or worried he seems, he always makes time to visit Pipit, to share a few tales of his adventures and hear stories of Skyloft and its people from Pipit, in return.
They rarely talk of much else. Link, because he doesn't have much to say at the best of times, a trait with Pipit has always admired, and Pipit, because he is afraid of what he might say. Because, if he let himself speak freely, he might ask Link to stay. To let someone else find Zelda, to let her take care of herself. Which is not fair, or reasonable, and which goes against the words of the Goddess herself. But there it is. Pipit wishes that Link would stay.
So instead of asking him for something that he can not, will not, even should not give, Pipit listens to his tales with quiet attention, smiles and ruffles Link's hair under his new cap, and memorizes that earnest look Link gets in his eyes, to make sure he does not forget it when he is gone.
And if that is all he gets, well. That will have to be enough.