Even a show about nothing has to have some patterns, right? Well, perhaps it does, but the theory that every Seinfeld episode contains a Superman reference has proven itself to be wholly untrue. Hopeful fans have tried to dig through and find whatever obscure reference they can, but at some point obscure becomes nonexistent. In the episode called “The Subway” for example, there are no references in the script to any of the characters or situations from Superman. Even the most persistent fan cannot find any reference. 

Every myth results from some truth, and what is true is that Superman references play a large role in the Seinfeld shows. This, however, results solely from Seinfeld’s love of Superman and not the deliberate inclusion of Superman in every episode. Superman also gets an added appearance as a magnet and figurine in Jerry’s apartment, though these were not added until the 4th and 5th season, and the apartment itself does not feature in every episode.