Two U.S. lawmakers with antitrust oversight have urged the Obama administration to carefully review a planned merger of American Airlines and US Airways Group to ensure that it will not lead to higher prices for air travelers, Reuters reported yesterday. US Airways announced on Feb. 14 that it planned to buy American Airlines parent AMR Corp., which is restructuring in bankruptcy court. The airlines are looking to complete the deal by the end of September. Senator Amy Klobuchar (D-Minn.), who chairs the Senate Judiciary Committee's antitrust subcommittee, and Mike Lee (R-Utah), the top Republican on the panel, said that the deal would mean the top four U.S. airlines would control nearly 90 percent of the U.S. market. The pair acknowledged in a letter yesterday that there could be efficiencies associated with the deal, but also noted concern that flight costs could go up or customer service could deteriorate.