Expedia has made it harder to find flights from American Airlines on its site in retaliation against American's decision to pull its flights from online travel rival Orbitz.

Earlier this year, American's contract with Orbitz expired, and the airline wanted to use the opportunity to change how it distributes tickets.

Today, American and other airlines pay global distribution systems like Galileo (owned by Travelport) to carry their flight information. Orbitz, Expedia, and other agencies then get their information from these distributors. American wants to cut the middleman out, which will save it money and let it make direct pitches for related services like car rentals and hotels. Orbitz doesn't like the precedent, as it gives the airline too much control over its business.

Now, Expedia has decided that American's actions are a threat to its business as well. When users search for flight information on Expedia's site, American is listed last among airlines and users must manually select a "See flights" link in order for the actual flight information to show up.

In a statement, Expedia said it made the move "in light of both American Airlines’ recent decision to prevent Orbitz from selling its inventory, and a possible disruption in Expedia’s ability to sell American Airlines tickets when our contract with American Airlines expires." Expedia didn't say when that contract expires.