A US District Court judge in Fort Worth, Texas, denied a motion by internet firm Google to dismiss a copyright infringement lawsuit filed by American Airlines.

Judge John McBryde rejected Google's motion without explanation in a court decision dated October 24.

The airline sued Google in August for selling the carrier's branded terms as search keywords.

"We are pleased by the judge's order denying Google's motion to dismiss our claims," an airline spokesman says in a statement. "American would not have brought its lawsuit against Google if we did not believe in the merits of our claims, and the court's order ensures that we will have an opportunity to develop and pursue those claims."

Google's lawyers oppose the lawsuit on competitive grounds.

"American's complaint is an illegitimate attack on competition, not a legitimate claim for trademark infringement. A party cannot infringe a trademark if it does not use a trademark as a trademark," Google says in a court document filed October 22.

Google was not immediately available for comment concerning the latest court action.

American Airlines is attempting to legally prohibit Google's practice of using the airline's branded terms and also seeks to recover undisclosed damages, a spokesman said previously.

"Our trademarks are being sold by a profit to somebody else," the spokesman said.

The complaint is focused on Google's AdWords program, which allow companies to "sponsor" search keywords. For example, if a Google user searches for "American Airlines tickets", several "sponsored links" appear on the results page. The links are paid advertisements based on the keyword search.

Although the oneworld alliance member is fighting Google in court, the carrier appears concerned about a consumer backlash for challenging the popular search engine.

"American wants to make it clear that its dispute does not seek to prevent the display of search results that reflect consumers' interests or choices," the company said in a previous statement.

"American is only asking Google to stop selling our trademarks to others who are purchasing them and related terms to confuse and/or divert consumers searching for www.AA.com or American's products, and we are seeking relief for the damages such practices are creating."