In 1941, during a staff meeting in Washington, D.C., two U.S. Army Air Corps officers square off over where the war’s real edge will come from. Major Chick Davis [Pat O'Brien] argues that a top-secret bombsight will be the spearhead of the striking force, while Captain Buck Oliver [Randolph Scott] contends that the priority is training fresh pilots. To settle the debate, they stage a bold test: Oliver uses a dive bomber and misses a stationary target, but Davis, bombing from 20,000 feet in a Boeing B-17 Flying Fortress, hits his mark with the first bomb.
As the first class nears graduation at the new bombardier training school, Davis arrives with M/Sgt. Archie Dixon to take command. Davis is unsettled by the presence of so many civilian women clerks, including Burton “Burt” Hughes [Anne Shirley], the daughter of a respected Air Corps general who now works as a secretary. Davis’s brusque manner meets Burt’s sharp observations, and she notes that he could use some training in manners. Oliver arrives with the next cadet class, which includes Tom Hughes [Eddie Albert], Burt’s brother. Davis learns that Burt and Oliver share a romantic history, and he makes a tentative effort to smooth things over with Burt.
Preflight ground school exposes a few troubling weaknesses: Tom Hughes struggles with fear-induced air sickness, Joe Connors [Robert Ryan] shows commitment issues, and Chito Rafferty [Richard Martin] laments the lack of women on the base. Connors warns Davis that a spy is trying to buy information about the secret bombsight, and together they lure the would-be traitor into a trap where he is arrested. When a bomber develops mechanical problems and the crew must bail out, Tom hesitates and refuses to jump. His friend Jim Carter [Walter Reed], another cadet and Burt’s suitor, crash-lands the aircraft, later insisting he was the one who panicked, but Hughes confesses. Facing an elimination board, Hughes persuades Davis and earns a second chance.
On a subsequent flight, Oliver nearly tosses Carter out of the bomb bay when he faints from a lack of oxygen, and Tom Hughes meets his fate: he falls to his death while saving Carter’s life. Guilt-stricken and unable to face Burt, Oliver transfers out of the school. After Pearl Harbor, the war widens, and Davis is promoted to colonel, becoming a B-17 group commander who awkwardly proposes marriage to Burt—which she declines. The cadet class moves on: Carter, Connors, Rafferty, and Harris depart for a secret island base in the Pacific, with Burt sharing a goodbye kiss and revealing her chosen partner.
At the new base, Oliver—now a major—joins the group just as it prepares for a night mission to bomb an aircraft factory in Nagoya. His assignment is to drop incendiaries to start fires, half an hour before the main group arrives, led by Davis at high altitude. Joe Connors is Oliver’s bombardier, with Dixon [Archie Dixon’s actor is Barton MacLane] as the tailgunner. Flying low, Oliver’s bomber is shot down before he can drop his bombs, and Connors remains at his post, sacrificing himself to ensure the bombsight is destroyed. Oliver and Dixon are captured by their Japanese captors, who execute the rest of the crew to force Oliver and Dixon to reveal the base’s location. Dixon manages a desperate escape attempt but is machine-gunned; his actions also ignite a truck carrying gasoline, setting the factory ablaze. Oliver drives the burning truck through the flames, exposing camouflage netting and completing the mission, fully aware he will be killed by his own men. The remaining B-17 squadron fights off enemy fighters and achieves a devastating, hard-won victory by destroying the Nagoya factory.
