DALLAS (AP) – American Airlines is suing Sabre to stop the company from downplaying American flights in displays that it provides to travel agents.

In a lawsuit filed Monday in state court in Fort Worth, American said it could lose “countless sales” if Sabre is allowed to favor listings of other airlines in data searches.

It’s the latest blow in an escalating fight over how airline tickets are sold.

American, a unit of AMR Corp., wants to force travel agents to get information about flights and fares straight from the airline to reduce its middleman costs. American also thinks it could sell more add-ons such as upgrades and in-flight Internet access if it provided flight information directly to travel agents.

As the rift has grown, online travel agencies Orbitz and Expedia have stopped displaying American flights, forcing consumers to visit other websites to buy American tickets.

Sabre Holdings Corp. joined the fight last week by making it harder for travel agents to find information about American flights and raising fees that it charges American. Sabre also plans to end a contract with American in August.

American called Sabre’s moves anticompetitive and anti-consumer by slanting information viewed by travel agents before they book flights. It asked a state court judge to issue an injunction to immediately block Sabre from burying its listings.

Sabre was created by American decades ago and revolutionized how airline reservations are made. It was spun off into a separate company several years ago. It is a key conduit between airlines and much-prized business travelers, who tend to fly more and pay higher fares than leisure travelers.

Airlines pay travel websites and middlemen such as Sabre, called global distribution systems, fees every time a consumer searches a flight or buys a ticket on one of the sites. The GDS gets on average $6.20 for a roundtrip nonstop itinerary or $12.40 if the traveler makes one stop in each direction, according to the airlines.

AMR shares fell 6 cents to close at $8.79.

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