A U.S. military helicopter flew over an elementary school next to an air base in Okinawa on Friday afternoon despite a promise to avoid doing so, Japanese government sources and the U.S. Forces said.The U.S. military made the promise after a window fell from a CH-53E chopper onto the grounds of an elementary school there in December.The Marines admitted a helicopter flew over the Futenma No. 2 Elementary School on Friday, and said an investigation has been launched."Although U.S. Forces voluntarily ceased flights over the school to the greatest extent possible, a U.S. helicopter inadvertent…READ FULL ARTICLE