Rule 240 airline urban legend or unspoken law?

Question: I fly down to Cabo San Lucas, Mexico, two or three times a year, and I’m curious: Does Rule 240 apply only to domestic flights?

--Harold Goerss, Woodland Hills

Answer: Yes. No. Maybe.

Because there either is or is not a Rule 240, depending on which side you’re on.

This mysterious bit of airline lore reminds me of tales of Prohibition-era speak-easies: You utter the magic words and cool things happen.

In this case, if you’ve had a misconnect on your airline or you’ve been delayed because of something the carrier has done, you approach an airline desk and say, “Rule 240 me, please.” And then you get on the next flight, sometimes even in first class.

People swear this happens in modern times. Other people swear the airline agent either doesn’t know what in the hum you’re talking about or starts laughing.

Before 1978, Rule 240 did exist.

In those days, when the airlines were regulated and carriers gave their lists of rules to the feds, No. 240 promised that carriers would help passengers reach their destination if the problem was something the airline created. Kazam! Doors opened, and you were on your way.

Then the government got out of the regulation business.

Some say 240 survives. “It’s still there,” says George Hobica, creator of Airfare Watchdog.com, which searches out lowest fares. “You just have to fly with an airline that has a 240.”

But don’t search for Rule 240 on a carrier’s website. Instead, look for contracts or conditions of carriage. Some of the rules are generous, promising first-class passage. Others are, well, less so, promising nothing.

Joe Brancatelli, editor of the business travel website JoeSentMe.com, calls 240 an urban legend. The re-accommodation rules contain “nothing serious,” he says. “All of them are full of loopholes.”

You’ll have to determine for yourself by reading the conditions of carriage from your airline, whether it’s domestic or international (although European Union rules supersede airline rules -- but that’s another story). Print them out. Carry them with you. Point to the contract and you may get a fair shake.

Me, I’m not exactly the eternal optimist when it comes to airlines. In fact, if I wanted a fair shake, I’d go to McDonald’s and ask for chocolate. Which is more than we get from the airlines.

Have a travel dilemma? Write to travel@latimes.com.