War Birds: Diary of an Unknown Aviator (2003)

Three young men from the South known as the 'Three Musketeers' fly with the Royal Air Force in World War I. One, John McGavock Grider, is killed in action. His diary is published after the war and becomes a huge publishing success. Much later it is revealed that the diary was actually written by his friend Springs, who felt responsible for Grider's death.