Prior to the United States' entrance into the war, a group of young Americans--Chuck S. Brewer, Johnny M. Coe and Wadislaw Borowsky--cross the Atlantic to fight the Nazis with the British Royal Air Force. They are assigned to the Eagle Squadron, which is made up of American flyers. Aboard their transport plane are squadron leader Paddy Carson, section leader Anne Partridge and transport aviatrix Nancy Mitchell. Chuck takes an immediate interest in Nancy, but she tells him that her boyfriend is his fellow flyer, Hank Starr. Just before their first mission, the flyers are warned about the German's new plane, which is twice as deadly as the previous one. While Johnny takes the company's feline mascot along as a good-luck charm, another flyer, Leckie, receives a garter from a female British spotter. The squadron then successfully attacks a German air force base. On the way back, however, Johnny and Chuck are shot down. Chuck parachutes into the sea and is successfully rescued, but Johnny is killed. A German flyer later parachutes the kitten back to the squadron, with a challenge for other flyers to join Johnny in death. When Chuck complains about the English's callous attitude toward death, he is informed that Johnny was killed because the two new flyers broke formation and that two other pilots were killed as well trying to protect them. Later, Chuck goes to a military dance, where he becomes reacquainted with Anne. During the dance, a German squadron attacks and Chuck helps save a young man's life. Anne later makes a date with Chuck, but when Carson hears of it, he tries to warn the young pilot off, but the jealous Chuck rebukes him. Anne's date turns out to be an excursion with a group of evacuated children. After a German raid interrupts their picnic, Carson whisks Anne away to London, much to Chuck's annoyance. The British then plan a commando raid into France, to steal one of the new German planes. Carson is set to lead the raid, and he requests that Chuck and Wadislaw join him. On his one-day leave, Chuck travels to London, in hopes of finding Anne and Carson. During a blitzkrieg, he finds the two at a burning hospital. Anne is injured leading a group of patients out of the burning building, but she finds there what she and Carson have been seeking: her missing father, pacifist Sir James Partridge. He dies in her arms, and Carson explains to Chuck that Partridge had flown incognito as a gunner on a British bomber, in attempted retribution to his dead soldier son Eric, who had been Carson's best friend. Now knowing the truth, Chuck proposes to Anne, but she refuses, stating that everyone she allows herself to love has been killed in the war. As the commando raid begins, Wadislaw takes Johnny's kitten along for luck. As a diversion, the commandos plan to attack the German air field, allowing Carson and the flyers to sneak onto the base in search of the plane. When the kitten wanders away from Wadislaw, however, he beings shooting. With the element of surprise lost, the attack is called off, but Wadislaw is killed and Carson fatally wounded. While Chuck stays behind with the injured squadron leader and steals one of the German "Leopard" planes, Carson is killed providing ground cover. Chuck then shoots down three German planes and successfully lands the stolen plane on British soil. Chuck and Anne are both decorated for their bravery, but the ceremony is cut short by a German raid. Chuck kisses Anne on the cheek, then takes to the air once more.