( CNN ) -- The U.S. Supreme Court has cleared the way for American Airlines and US Airways to merge into world 's largest airline company . Late Saturday night , Justice Ruth Bader Ginsburg declined to hear a stay request filed by a consumer group opposing the merger . Earlier in the day , a federal appeals court in New York also denied an emergency stay -- which prompted the consumer group to turn to the Supreme Court to block the deal . The passenger group believes that a merger will result in higher fares and reduced choices for fliers . With the Supreme Court removing the last roadblock , the two airlines can sign papers before the financial markets open Monday . For the foreseeable future , though , passengers will still be booking flights under both the American Airlines and US Airways names . Details about when the airlines will combine reservations and ticketing , frequent flier clubs and other operations are still being worked out , and those combinations are not likely until the beginning of 2014 , at the earliest . But the combined company will be the largest airline in the world in terms of revenue , passengers carried and the number of miles flown by paying passengers , surpassing United Continental Holdings , which was also formed by a merger . CNN 's Supreme Court producer Bill Mears contributed to this report .
Justice Ruth Bader Ginsburg declined to hear a stay request . Passenger group believes merger will result in higher fares and reduced choices . The two airlines can sign papers before the financial markets open Monday .