An overgrown airfield on a small island in the Pacific, once instrumental in America's role in ending World War II, is being reclaimed by the U.S. Air Force as it prepares for a future fight with China. The remote island of Tinian, which is less than 40 square miles, is one of three principal islands in the Northern Mariana Islands, a string of sparsely populated islets in the Western Pacific Ocean that make up the U.S.'s westernmost frontier, along with the major military hub of...