KARLSRUHE, Germany — U.S. Senior Airman Nicholas J. Alden was standing outside of a bus at Frankfurt airport when a young man first asked him for a cigarette, then whether he was bound for Afghanistan. When Alden answered yes, the man fatally shot him, point blank, in the back of the head, then stormed aboard the bus shouting "Allah Akbar" — Arabic for "God is great." He shot and killed Airman 1st Class Zachary R. Cuddeback, who was at the wheel, then shot and injured two others, German authorities said Friday. The gunman, identified as Arid Uka, a 21-year-old Kosovo...