Q. I haven’t flown for several years, preferring to drive instead. One reason is that last time I flew, my flight was cancelled due to mechanical problems. However, the airline (American) did put me on another airline at no extra charge to get me to my destination, and although we were still several hours late, it was better than sleeping on the airport floor. I need to fly to a wedding in February and wonder if United still has this policy in the event of a cancellation. What about other airlines?

A. As a matter of fact, according to United’s current contract of carriage, yes it does. You were protected under a clause called “Rule 240” in United’s contract, which states that in the event of a “flight irregularity,” if United Airlines (UA) “is unable to provide onward transportation acceptable to the passenger UA…will arrange for transportation on another carrier…with whom UA has agreements for such transportation…in the same class of service as the passenger’s outbound flight at no additional cost to the passenger.” Some airlines, but certainly not all, have similar rules in their contracts. Alaska Airlines, for example, will even put you in a higher class of service (i.e., first class) on another airline if that’s the only option to get you to your destination faster than you’d arrive on one of Alaska’s own flights, as will Hawaiian Airlines. However, other airlines are not so accommodating. Most airlines formed in the years after carriers were deregulated by the government, such as AirTran, JetBlue, and Spirit, have no such language in their contracts. Nor does American Airlines. Delta, Southwest, and US Airways use terms such as “may attempt to rebook the customer…on another airline” or  “at our sole discretion we may arrange for travel on another carrier.” Virgin America’s contract states that it “may…substitute alternate carriers.” Obviously, “may” is not exactly an iron clad guarantee.  Even so, JetBlue and other airlines with iffy language have been known to reroute passengers on other airlines in the event of a cancelled or delayed flight, but all airlines have clauses in their contracts absolving themselves of responsibility if the delay or cancellation is beyond their control, such as a weather event, strike, or, say, a volcano. Even so, it’s a good idea to locate your airline’s contract of carriage before your next flight and give it a good read. These contracts are full of interesting information spelling out what rights you may—or may not—have. Most of these are in PDF form and can be found by doing an online search under “contracts of carriage.”