The cost of buying American Airlines flights through many UK travel agents rose today after the carrier imposed fees on bookings through global distribution systems (GDSs) Galileo and Worldspan.

GDS-owner Travelport dismissed the charges as “wholly arbitrary”, but immediately applied them to American Airlines fares in a move it believes will lead agents and customers to switch to other carriers.

Agents use the systems to access fares and book flights, traditionally at no cost. But American Airlines is charging £4.52 per flight on Worldspan and £6.24 on Galileo from today as part of an escalating row with Travelport. Rival systems Sabre and Amadeus are unaffected.

Lawyers for Travelport and American Airlines were in court in Illinois last week seeking a ruling in a case brought by the GDS owner after the carrier withdrew fares from US online retailer Orbitz, in which Travelport owns a major stake. The airline said it would end sales through Orbitz on December 1.

Travelport promptly sued and withdrew discounts on its charges to American Airlines for appearing on the GDSs, and American Airlines responded by warning agents it would impose fees to compensate from December 20.

American Airlines UK sales director Graham Bell told UK agents: “American will ask you to absorb the cost . . . known as the Booking Source Premium.”

The airline planned to levy the charges via IATA automated debit memos (ADMs) from February. But in a statement today Travelport said the fees would be shown in fare displays and charged to customers at the point of booking.

Travelport said: “This booking source premium will be collected along with other fees and charges and remitted directly to AA, obviating the inconvenience and cost to travel agencies of having to deal with ADMs.”

The technology company slammed the charges as “wholly arbitrary”, suggesting they “do not bear any discernible relation to what Travelport charges AA”.

Travelport’s statement placed the blame solely on the airline, arguing: “This issue has been precipitated [by] American Airline’s actions [in] withdrawing ticketing authority from Orbitz.

“This is clearly not an isolated incident concerning one US-based travel agency and AA. Rather it is an attempt by AA to fundamentally change an existing distribution model.

“Insofar as AA’s surcharge fee will inevitably cause some disruption, we regret any inconvenience to our travel agency customers.”

Agents can avoid the charges by bypassing Travelport and booking direct through American Airlines’ Direct Connect facility.