To the best of my knowledge, Rule 240 originated before deregulation by the Civil Aeronautics Board (CAB). It was a domestic rule between the carrier and the passenger to get them from the origin to the destination. Today, it has become a set of rules due to the various tariffs and fares. Different airlines also have different ways of expressing the rule. I would like to know what the original rule looked like. It would be helpful to understand the original CAB rule before reading into the various airline 240 rule(s). Does anyone know where to find the original Rule 240?