Ace of Aces (1933)
Ace of Aces (1933), also known as Bird of Prey, was a war film, based on the story The Bird of Prey by World War I pilot John Monk Saunders that explores how war can turn a man's moral compass from pacifism to warmonger. Starring Richard Dix, it was similar to many of the period films that appeared to glorify the "knights of the air", but was more complex, examining the motivations of those who choose to go to war.
More at Wikipedia.