President Donald Trump ordered the U.S. Navy to remove the Electromagnetic Aircraft Launch System, or EMALS, from future Ford-class aircraft carriers and return to older steam-powered catapults and hydraulic systems, a reversal that has drawn criticism from Sen. Mark Kelly and could add billions of dollars in redesign costs. Kelly, an Arizona Democrat on the Senate Armed Services Committee, said the change would affect ships already deep into development, including the Doris Miller, and argued Trump was not qualified to dictate carrier engineering decisions. Trump has attacked EMALS for years as too expensive and complicated, but the Navy said in February that preliminary testing aboard USS Gerald R. Ford showed EMALS and Advanced Arresting Gear helped generate a higher aircraft launch rate than on Nimitz-class carriers. The dispute highlights a clash between presidential preference and the Navy’s modernization plans for its newest carrier class.