Log onto American Airlines for a flight from Chicago to London in mid-April, say, and it shows six daily nonstop flights, all with American Airlines flight numbers. But you also see "operated by British Airways" on two of the six flights. Welcome to the world of code-sharing, where "airline A" makes a deal with "airline B" to place airline A's flight numbers on airline B's flights. The ostensible benefits to travelers are (1) to allow an airline to display and sell flights to more places than it can by itself and (2) to make ongoing connections between the code-sharing airlines more "seamless." Whether you buy into that rationale is immaterial; code sharing is here to stay for the foreseeable future.
Even if the benefit claims are inflated, ideal code-sharing should at least be relatively benign and transparent. Unfortunately, in practice, code-sharing generates a handful of gotchas that can really surprise you if you aren't aware and careful.
To avoid those gotchas, when you search a trip, somewhere during the purchase process, the airline or OTA will tell you if your flight is a code-share operated by a different airline. Be sure to look for it. If a flight that you like is a code-share, check fares and other details on both airlines, and revise your request if you see a better option.
Gotcha 1: Fare Variances
Often, on a code-shared flight, airline A's fares are different from airline B's. On the quick test of flights from Chicago to London departing April 11, all six daily nonstops are code-shared and all six could be booked through either the American or British Airways website. On that particular test, the fares for the morning flight, flown by American, were equal at $722 round-trip. On the five other flights, British Airways fares ranged from $90 to $130 less than American, regardless of which airline flew the flight.
On other routes, among other airlines, there is no pattern of consistency in terms of routes or airline home countries. If you find a flight you like, and it is code-shared, always check the partner line's fare to see which is the best.
Gotcha 2: Frequent Flyer Variations
On a code shared flight, your frequent flyer earnings are based on the program of the airline on which you bought the ticket. Difference in frequent flyer earnings could easily offset a minor fare difference.
Gotcha 3: The Terminal Shuffle
Although airlines that code-share typically try to locate their ticketing and boarding facilities convenient to partner lines, that is often not possible. No matter the airline named on the ticket; the plane leaves from the terminal of the airline that flies the flight. So unless you know that you're on a code-shared flight, you might show up for American flight 6196 from O'Hare to London at American's departure area in Terminal 3 rather than the BA departure area in International Terminal 5, more than a mile distant. This happens at far more airports than just O'Hare.
Gotcha 4: The Re-Screening Hassle
A subset of Gotcha 3, at connecting airports, you encounter this one when you arrive at one line's terminal, and are forced to exit security, schlep to a different terminal, and to re-process through security and immigration to catch your connecting flight. Some giant hub airports outside the U.S. offer isolated "transit" status and airside transportation between terminals for connecting passengers; others do not. U.S. airports are notorious for not implementing "transit" status.
Gotcha 5: Product Differences
Just because a flight has an American flight number doesn't mean you get American's product. You get the hard product of the airline that flies the plane, or in industry jargon, "metal." Hard product differences are most apparent with business class, where, in the test example, American's hard product is generally considered much better than BA's. If you're anticipating American's hard product, the product on BA metal is likely to disappoint. Conversely, if you're fond of BA's cabin service, you might be disappointed by American's soft product. Hard and soft product differences are less pronounced in economy class, where they're all bad, but you still encounter minor differences in cabin service.
Gotcha 6: Missed Compensation
You've seen reports, here and elsewhere, about European rules requiring airlines to compensate passengers for delay or cancellation in cases where the U.S. does not. A whole cottage industry has arisen of outfits that help travelers recover compensation they're due in exchange for a slice of the action. Compensation is significant, up to €600 (about $740) for a transatlantic flight arriving four or more hours late. The European rules, in EU 261, require compensation for all flights that depart from an airport within the E.U. (plus Switzerland), including all flights to the U.S. and Canada, and to all flights arriving in the E.U. on airlines based in the E.U.
That condition means on a delayed flight from the U.S. to Europe, you're eligible for compensation when you're on a European airline but not when you're on a U.S. airline. And the determination is based on the airline that actually flies the plane, not the ticketing airline on a code-shared flight. So if you buy a ticket on BA that is actually flown on American metal, you aren't eligible.
Gotcha 7: The Other Guy Hassle
Originally posted on SmarterTravel in 2008, this observation drawn from a caper novel remains valid: Whether dealing with fellow conspirators or the police, “Otherguy Overby” always found a way to blame someone else when a caper went amiss. Although the story had nothing to do with the travel industry, the “other guy” effect surely does. Whenever two or more companies are involved in a trip, and something goes wrong, each is quick to pile the blame elsewhere. Code-sharing is an open invitation for both airlines to assume the guise of Otherguy Overby. The general rule is that if you have a problem, you take it up first with the company that took your money. But you can still encounter a lot of hassle.