Stout Feather is the hippogriff Fixit learned his trade from, as Ponyville doesn't really have much in the way of technical colleges. The ones in Canterlot cost too much, and he didn't want to go all the way to Fillydelphia. Fortunately, Stout Feather lives in Ponyville and is rather a bit of a mechanic himself, so he took on Fixit as an apprentice when he was a colt.