President Donald Trump is ordering the U.S. Navy to remove the advanced system used to launch fighter jets from its newest type of aircraft carrier and return to using older steam catapults that he has long said he prefers, according to a directive issued Thursday. The new mandate would likely cost billions of dollars and revert the Navy’s most advanced ships to a system that takes more sailors to operate and is more difficult to maintain. The memo directs the Pentagon and the Navy to present Trump with plans to remove the Electromagnetic Aircraft Launch System, also known as EMALS,...