American Airlines and US Airways Group Inc. agreed to extend the deadline for completing their $14 billion merger until Jan. 18 as the carriers prepare to fight a U.S. antitrust lawsuit to block the combination.

The boards of both American parent AMR Corp. and Tempe, Arizona-based US Airways approved moving the deadline from the original Dec. 17 date, the companies said in a U.S. regulatory filing.

The merger, which will allow American to leave bankruptcy protection, has been put on hold pending resolution of the U.S. Justice Department’s claims that the combination would hurt consumers by reducing competition and raising fares. The airlines have said the new American would have the heft to compete effectively with larger Delta Air Lines Inc. and United Continental Holdings Inc.

US Airways Chief Executive Doug Parker will be CEO of the combined carrier, which will keep the American name and its headquarters in Fort Worth, Texas. American Chief Executive Officer Tom Horton will serve as chairman until the first annual meeting of the new American.

The antitrust case is U.S. v. US Airways Group Inc., 13- cv-01236, U.S. District Court, District of Columbia (Washington). The bankruptcy case is In re AMR Corp., 11- bk-15463, U.S. Bankruptcy Court, Southern District of New York (Manhattan).

Editors: Niamh Ring, Stephen West. To contact the reporter on this story: Mary Schlangenstein in Dallas at maryc.s@bloomberg.net. To contact the editor responsible for this story: Ed Dufner at edufner@bloomberg.net. 

Photo Credit: Dozens of flight attendants, pilots and airline union members rallied in front of the Capitol Wednesday, September 18, 2013 in Washington, D.C., in support of a merger that would create the world's largest airline. () Olivier Douliery / Abaca Press/MCT