American Airlines’ plan to exit bankruptcy protection by merging with US Airways Group Inc. was approved by a judge who said a U.S. antitrust lawsuit seeking to block the deal was no reason to delay it, Bloomberg News reported yesterday. The chapter 11 reorganization plan by AMR Corp., the parent of American Airlines, can’t take effect until the combination gets regulatory clearance, Bankruptcy Judge Sean Lane said yesterday before approving the deal. “There can be no dispute that the plan is feasible if the merger succeeds,” he said. Judge Lane, who challenged a $20 million severance under the turnaround plan for AMR Chief Executive Officer Tom Horton, said it’s not uncommon for plans to be accepted under a cloud of regulatory uncertainty.