A federal judge on Friday rejected a last-ditch effort by consumers and travel agents to stop American Airlines and US Airways from merging next week, which they fear would drive prices up and service down and make planes more crowded. The combination of American's parent AMR Corp and US Airways Group Inc (NYSE:LLC) would create the world's largest carrier, and would follow last month's resolution of antitrust objections by the U.S. Department of Justice. That settlement requires the airlines to shed some landing slots and gates at several airports, including in New York and Washington, D.C., and had won approval on November 27 from U.S. Bankruptcy Judge Sean Lane, who oversees AMR's Chapter 11 case. AMR has said it hoped to complete the merger on December 9. (Reporting by Nate Raymond and Jonathan Stempel in New York; Editing by Gary Hill)