Twelve O'Clock High - 1949 - Henry KIng

This is considered one of the better Hollywood war movies and represents another collaboration between Henry King and Gregory Peck.

It's a fictionalized account of the struggles of American pilots in their daytime bombing campaigns against German industrial centers during World War II. When a very kind and understanding commanding officer cannot seem to handle the demanding responsibilities of leading his men in regard to missions that entail immense emotional stress, pain and hardship, a new commanding officer is brought in to take exactly the opposite approach - he becomes a severe disciplinarian who sets high standards and requires a 'maximum effort' from everyone.