It’s true that the ticket is a contract. The consideration paid by the passenger is money, not riding the plane. Giving a plane ride is the consideration given by the airline. The only way the passenger can breach the contract is by not paying for the flight. When the passenger actually flies, that actually costs the airline money (especially when they are able to sell the empty seat to another passenger). Something that actually costs the other party to a contract money can’t be consideration.

The real reason for the policy is 1) to extract money from people, and apparently (per Joey) 2) to combat use of promotional fares. That’s fine, but the downside of trying to use price discrimination (in the economic sense, perfectly legal and reasonable) between business and leisure travelers is it leads to bizarre and byzantine business practices that drive people to Southwest, AirTran, etc., as it did with Joey and the blog host.

I recently ran into a similar situation, but knew I would need to buy a one-way back because, if you can think of a way that a major airline will screw you, they will do it. I chose a different carrier for the trip back. Unfortunately, Southwest had just discontinued the route I needed, or I definitely would have used them.

We just received notice of major changes in your flights to/from Cancun. American canceled their non-stop flights. They are offering flights requiring one change of planes in each direction. You would leave O’Hare at 7:55 a.m. (instead of the original departure time of 8:15), and arrive in Cancun at 1:40 p.m. (instead of 11:45 a.m.). Your return flight would leave at 2:40 p.m. (instead of 1:45), arriving in Chicago at 9:15 (instead of 5:25).

At the moment, we can get you on non-stop Mexicana flights, leaving O’Hare at 10:25 a.m., arriving in Cancun at 2:15 p.m. and returning at 2:45 p.m., getting back at 6:40, for $292. (Neither flight availability nor air fares are guaranteed until paid in full.) The American flights cost you $292.69 per person, so the total cost wouldn’t change significantly. However, although it would we would have to cancel the American flights and get you a full refund of $585.38, which might take a few weeks to show up on your credit card. Meanwhile, you would have to pay for the Mexicana flights in full. Alternatively, you could just accept the American proposal.