The worst case of friendly fire in American history, to my knowledge, is the night of July 10/11 or 9/10 (?), 1943. "On one night during World War II _ July 9-10, 1943 _ 23 U.S. troop transports carrying paratroopers of the 82nd Airborne Division were shot down by American forces in Sicily who mistook the planes for German bombers. The death toll in that single friendly fire incident was 410. " Any others?