Be conscious of code sharing

According to airport flight schedules, each afternoon at 2:15 p.m. six airlines provide service from Pittsburgh International Airport to JFK International Airport in New York City. ExpressJet 2052, Air Europa Lineas Aereas 3148, Northwest 5132, COPA 2952, Alitalia 3953 and Continental 2052 are all scheduled to arrive at 3:39 p.m.

Traffic jam in the sky? Not really, because although six departures are listed on the flight board, only one plane actually takes to the air, an Embraer regional jet with 37 or 50 seats operated by ExpressJet Airlines, a Houston-based affiliate of Continental Airlines. The other five carriers are only along for a marketing ride.

Welcome to the world of code sharing.

By definition, code shares are arrangements in which one or more carriers market services and places their flight codes on another carrier's departure. For airlines, it's a win-win situation. The carrier operating the flight gets a boost filling its planes, and the others get to offer passengers service to destinations not in their normal route structure.

For most purposes, the booking is treated as one journey. In the case mentioned, any of the five code-share carriers can sell a ticket on that flight, but it's an ExpressJet flight operated by ExpressJet pilots and flight attendants on ExpressJet routes.

Code sharing has been legal since Congress deregulated the domestic airline industry in 1978, but until recently, these arrangements were usually made between U.S. carriers and foreign carriers. For example, US Airways has been a participant in the Star Alliance, which numbers 15 foreign carriers, as well as United Airlines.

However, over the past decade, as airlines have scratched for every way to cut costs, code-sharing agreements have become increasingly common on domestic routes. In addition, while the Department of Transportation must approve code shares with foreign carriers, there's little oversight on entirely domestic arrangements unless it's shown to be an anti-competitive situation.

The airlines say that code shares are good for passengers because they improve coordination between connecting flights, streamline baggage transfers and offer the convenience of a single ticket for multiple flights. Furthermore, code sharing usually permits passengers to collect frequent-flier credits on one carrier and use them for free seats on a partner.

But some consumer advocates have different opinions, calling code sharing confusing and misleading. Although code share flights are supposed to be clearly designated on booking, reservation and travel documents, passengers regularly report showing up to check in at the ticket counter only to be directed to the airline actually operating the flight. This is particularly a problem when catching a connecting flight in a distant airport.

Similar confusion can crop up if you're expecting the wrong airline to deliver your luggage at the other end of the flight.

But when everything goes smoothly, code-share transfers between the carriers and passengers should proceed seamlessly.

The primary problems come when there are hitches. If flight schedules are interrupted, for example, passengers must usually rely on the carrier that issued the ticket to make changes. On the other hand, when luggage goes astray, it's generally the operating carrier's job to find it. To harried passengers in an unfamiliar airport, the back and forth can be an exasperating run-around.

Complications also can arise if you need to change your itinerary or seat assignment. Generally, you need to contact the carrier that issued the ticket, but there are exceptions. Southwest specifically states that changes on code share flights it operates with ATA must be made with ATA.

Curiously, there also can be differences in the prices that different carriers charge for the same seat. Usually, it's a matter of $10 or $20, but since airlines are free to set rates in code-sharing situations and they generally prefer to preserve their own pricing structures, the variations can sometimes be hundreds of dollars.

The general advice to passengers: Be conscious of code sharing. When shopping for reservations, check all the options to your destination and see if there's a code-share partner that offers a better deal than the primary carrier. The secondary airlines are required to designate their flights are actually a code share, but they don't always make it obvious. For example, the US Airways Web site will include an asterisk in its flight numbers when any leg of the journey is operated by another carrier. On other carriers, the numbers of code-share flights may include the original sequence of the operating carrier's departure.

Another way to find out is by checking a Web site such as www.flightstats.com that lists all the code-share offerings on any particular flight.

Of course, when it comes time to travel, be aware if any leg of your journey is on a code-share flight. That information should be printed on your travel documents. That way, you'll know where to check in, where to fetch your luggage and where to turn if there's a problem.