The merged American Airlines - US Airways would be the world 's largest airline . The merger , which would create the world 's largest airline , would `` substantially lessen competition '' for commercial air travel , contends the complaint , filed in U.S. District Court in Washington . Lawsuit : The merger would ` ` substantially lessen competition '' for air travel . Previous mergers won approval in recent years amid the poor economy , but it now loses money . NEW : American / US Airways say they will fight government attempt to block their deal .
The merged American Airlines - US Airways would be the world 's largest airline . Lawsuit : The merger would ` ` substantially lessen competition '' for air travel . Previous mergers won approval in recent years amid the poor economy , but it now loses money . NEW : American / US Airways say they will fight government attempt to block their deal .