A U.S. military helicopter on Sunday landed at an airport in Kagoshima Prefecture, southwestern Japan, without prior notification, the local government said. The municipal government said the transportation ministry’s bureau at Kagoshima airport had informed Yoron airport at around 2:50 p.m. that the U.S. helicopter would shortly be landing on the island. Commercial flights in and out of Yoron airport were not affected. The Japanese Ground Self-Defense Force and U.S. Marine Corps were carrying out an exercise dubbed “Iron Fist” on another island near the airport. The U.S. helicopter is believe…