During the first season, back when network TV was so timid, they would only allow Fonzie to wear his leather jacket in certain scenes like when confronting bullies or riding his motorcycle. He wore a grey windbreaker instead. However, in the sixth episode "The Deadly Dares" where Ritchie dresses in drag as part of initiation and Fonzie dances with him not knowing he's Ritchie, Fonzie has his leather jacket on. It's a school dance scene and I tended to wonder why they allowed him to wear the jacket in that scene. It was stupid censorship of course, but I think that proves that it was a very loose rule.