American wants travel agencies to access ticket prices direct from American, rather than going through middlemen called global distribution systems, or GDS, The Associated Press reported.
Orbitz CEO Barney Harford said the American strategy would make it harder for customers to compare prices.
Orbitz is controlled by Travelport Limited, which also owns two GDS.
American said in a statement that its tickets will still be available on Orbitz today and they will "continue to negotiate in good faith to reach a viable, mutually beneficial agreement with Orbitz."
Airlines have been working to trim costs as the economic slowdown and high fuel costs eat into profits.