Code sharing is a business term which first originated in the airline industry. It refers to a practice where a flight operated by an airline is jointly marketed as a flight for one or more other airlines. Most if not all major airlines nowadays have code sharing partnerships with other airlines, and code sharing is a key feature of the major airline alliances.

The term "code" refers to the identifier used in flight schedule, generally the 2-character IATA airline designator code and flight number. Thus, XX123, flight 123 operated by the airline XX, might also be sold by airline YY as YY456 and by ZZ as ZZ9876.

Under a code sharing agreement participating airlines can present a common flight number for

• Connecting flights

While obviously and importantly this paints a simpler picture to the customer, it is not only a cosmetic operation: cooperating airlines also strive to synchronize their schedules, making transfers between connecting flights less time-consuming.

• Flights from both airlines that fly the same route

The apparent frequency of service on the route is thus increased.

By using this possibility, carriers who do not operate their own aircraft on a given route may also gain exposure in the market through display of their flight numbers.

In Global Distribution Systems, such as Amadeus , Galileo , Worldspan, or Sabre, this results in the same flight details, except for the flight number, being displayed on computer screens excessively forcing other airlines flights to be displayed on following pages where they may be missed by passengers searching for required flights.

Much competition in the airline industry revolves around ticket sales (also known as "seat booking") strategies. Travel agents have a preference for flights which provide a direct connection. Code sharing gives this impression. Computer reservations systems (CRS) also often do not discriminate between direct flights and code sharing flights and present both before options that involve several isolate stretches run by different companies.

Criticism has been levelled against code sharing by consumer organizations and national departments of trade since it is claimed it is confusing and not transparent to passengers, but thus far without any success.

Code sharing between airlines and rail lines

There are also code sharing agreements between airlines and rail lines . They involve some integration of both types of transport, e.g. in finding out the fastest connection, allowing exchange between an air ticket and a train ticket, or a step further, the air ticket being valid on the train, etc. See also list of IATA-indexed train stations.

External link

• http://www.railwayage.com/jan01/planes_to_the_trains.html