The film follows a pilot and crew of a World War II-era Douglas C-47 Skytrain (the military version of the DC-3) who try to survive after a forced emergency landing in the uncharted wildlands near the Quebec-Labrador border. The pilot, Dooley (John Wayne), is a former airline pilot, who, like many others, was pressed into duty hauling war supplies across the northern route to England. Icy conditions force the aircraft to land, and with the difficulties of navigating far from settled country, they can provide only an approximate position to rescuers.
Pilot Jack Savage (Rod Taylor) is suspected of drinking and causing an airliner crash that kills 53 people and leaves only a single survivor, Martha Webster (Susanne Pleshette), a flight attendant. The captain's wartime buddy, airline executive Sam C. McBane (Glenn Ford), is convinced of his friend's innocence and investigates doggedly. Flashbacks deal with both Jack's past and Sam meeting him, plus others they used to know.
Major Cleve "Iceman" Saville (Robert Mitchum), a veteran World War II fighter ace, returns to combat, eager to fly an F-86 Sabre fighter. His commanding officer, Colonel "Dutch" Imil (Richard Egan), assigns him command of a flight.
In the Battle of France in June 1940, RAF pilots evacuate a small airfield in advance of the German Blitzkrieg. The pilots, along with British and French military, leave just as German aircraft arrive and execute a heavy strafing attack. RAF Air Chief Marshal Hugh Dowding (Laurence Olivier), realising that an imminent invasion of Great Britain will require every available aircraft and airman to counter it, stops additional aircraft being deployed to France so that they are available to defend Britain. In the next dramatic scene, French civilians watch in awe as a convoy of German troops march into France and take control.
Assigned to bomb a German railway, Flight Lt. Terrence Forbes (Errol Flynn) presses home an attack but flies too low and the RAF bomber is shot down near the former Polish border. Along with his crew, consisting of Flying Officer Johnny Hammond (Ronald Reagan), Flight Sergeant Kirk Edwards (Alan Hale, Sr.), Flying Officer Jed Forrest (Arthur Kennedy) and Flight Sergeant Lloyd Hollis (Ronald Sinclair) who is wounded, they are captured by the Germans.
1940 in Paris, Michele de la Becque (Joan Crawford) is a career woman in love with industrial designer Robert Cortot (Philip Dorn). Together they enjoy a luxurious lifestyle unfazed by the approach of World War II. After the Battle of France and subsequent German occupation, Michele discovers her lover is socializing with German officers and his plants are manufacturing weapons for them. She confronts him and he does not deny her evidence. She is outraged. She aids a downed American in the Eagle Squadron of the Royal Air Force bomber pilot Pat Talbot (John Wayne) from Pennsylvania and finds herself falling in love with him. Later, she discovers Cortot is turning out defective weapons for the Germans and organizing a French fighting force. Michele is happily reunited with Cortot.
A passenger airliner piloted by Bill Lonagan (Robert Ryan) and Joe Brooks (Keith Andes) is bound for Boca Grande, South America, making a pick-up stop in Central America. Passengers: Jud Ellis (Gene Barry) escorting his fiancé Louise Melhorn (Phyllis Kirk); repentant political assassin Vasquel (Rod Steiger) is being transported back to the proper authorities by detective Crimp (Fred Clark); mobster Pete Bostwick (Jesse White) is accompanying a little boy named Tommy, whose father is Bostwick's boss; an elderly couple, Professor and Mrs. Spangler (Cameron Prud'Homme and Beulah Bondi), are apparently on vacation; and jilted blonde bombshell Rena (Anita Ekberg), on her way to a South American casino, is vying for Ellis' attention.
Flight 7500 is departing from Los Angeles to Tokyo. Passengers on board include: a group of two vacationing couples, Jenn (Aja Evans) and Jack (Ben Sharples) and Brad (Ryan Kwanten) and Pia (Amy Smart), who have secretly broken up; a thief Jake (Alex Frost); a suspicious businessman travelling with a strange wooden box, Lance (Rick Kelly); a young woman Raquel (Christian Serratos); newlyweds Rick (Jerry Ferrara) and the snobby Liz (Nicky Whelan), and; the goth Jacinta (Scout Taylor-Compton). Air hostesses Laura (Leslie Bibb) and Suzy (Jamie Chung) welcome the passengers on board, and Suzy questions Laura about her secret relationship with the married captain, Pete (Johnathon Schaech).
Edgar Anscombe (Christopher Reeve) is an instructor at a US Army Air Corps flying school in 1918. While he is teaching a young pilot, the aircraft crashes during a landing attempt and bursts into flames. The student is killed, though Edgar survives.
Bill Forrester (Gregory Peck), a Canadian pilot serving in the Royal Air Force in Burma, flying de Havilland Mosquitos, a two-seat fighter-bomber. Forrester is emotionally distraught after losing his new wife in the ‘’Blitz’’ in London and has become self destructive, seeking to end his life in action. "You'd think that would be easy in a war", he explains to a Burmese woman, Anna, "but I just kept getting medals instead." With Anna's support, Bill begins to recover his emotional stability.
A la prison Hao Lo de Hanoi, rebaptisée "Hanoi Hilton", les prisonniers américains arrivent à partir de 1964. La guerre n'étant pas officiellement déclarée, ils sont traités comme des criminels ordinaires et subissent torture, faim, angoisse.
Upon reaching retirement age, Colonel Cornelius Stockton (Harry Carey) is forced to leave the US military, accepting a job running the Trans-World Air Lines School of Aeronautics in Glendale, California. "Stag" Cahill (Richard Dix), an old friend from the war, is the pilot on the commercial airliner taking him to Glendale. The colonel asks him to join the school staff, but Stag would rather fly. When the colonel arranges for Stag, a reservist, to be recalled to active duty, he orders him to take the assignment as his assistant. Stag reluctantly complies.
"B for Bertie" is an RAF Vickers Wellington bomber whose crew was forced to bail out over the Netherlands near the Zuider Zee after one of their engines was damaged during a nighttime raid on Stuttgart. Five of the six airmen find each other; the sixth goes missing. The first Dutch citizens they encounter, led by English-speaking schoolteacher Else Meertens (Pamela Brown), are suspicious at first as no aircraft is reported to have crashed in the Netherlands (the abandoned bomber actually reaches England before hitting a pylon). After much debate and some questioning, the Dutch agree to help, despite their fear of German reprisals.
During the First World War, two French aviators, aristocratic Captain de Boeldieu (Pierre Fresnay) and working-class Lieutenant Maréchal (Jean Gabin), embark on a flight to examine the site of a blurred spot on photos from an earlier air reconnaissance mission. They are shot down by a German aviator and aristocrat, Rittmeister von Rauffenstein (Erich von Stroheim). Von Rauffenstein, upon returning to base, sends a subordinate to find out if the aviators are officers and, if so, to invite them to lunch. During the meal, von Rauffenstein and de Boeldieu discover they have mutual acquaintances—a depiction of the familiarity, if not solidarity, within the upper classes that crosses national boundaries.