A U.S. bankruptcy judge yesterday held off approval of a restructuring plan for American Airlines, citing a U.S. government challenge this week to the airline's proposed merger with US Airways Group Inc., Reuters reported yesterday. American's parent company, AMR Corp, worked out the $11 billion merger with US Airways as part of a plan to exit bankruptcy, where it has been since 2011. Bankruptcy Judge Sean Lane had been expected to approve the plan at a hearing yesterday. But the U.S. Justice Department earlier this week sued to block the merger, saying that it would lead to higher fares and hurt consumers. Instead of approving the plan, Judge Lane gave AMR and its creditors until Aug. 23 to submit briefs on how he should proceed. Judge Lane said he needed more information about the appropriateness of approving the restructuring plan in light of the antitrust challenge.