Frequent flyers may experience the occasional bump from a full flight, but what do they do if they get bumped out of their frequent-flyer program? Well, they end up in the U.S. Supreme Court, of course!

The justices on Tuesday heard arguments in a case stemming from Northwest Airlines’ termination of Rabbi S. Binyomin Ginsberg’s membership in its frequent-flyer program. At its core, Northwest Airlines v. Ginsberg is about federal preemption under the federal Airline Deregulation Act. But in the courtroom, it seemed more like a primer on contract law.