Before the deregulation of airline fares and routes in 1978, carriers all had to follow the same set of rules to deal with “irregularities,” such as canceled flights. One of these rules, number 240, specified that if an airline couldn’t get you to your destination on time, it was required to put you on a competitor’s flight if that would get you there faster than the original airline’s next flight. Airlines even had to put you in first class if that was all that was available. Newer airlines, such as JetBlue, Southwest, and Spirit, are not required to follow these rules, but the so-called legacy carriers (American, United, USAir, Delta, Northwest, and Continental) still adhere to them. If you’re flying one of these older airlines, go to its website and print out a copy of Rule 240, if available, and take it with you. Present the copy to the gate or check-in agent if your flight is canceled, and the agent will put you on the next available flight free of charge.