Plot
In Honolulu, Hawaii, a DC-4 airliner prepares to take off for San Francisco, California with 17 passengers and a crew of 5. Former captain Dan Roman, the flight's veteran first officer, known for his habit of whistling, is haunted by an air crash that killed his wife and son and left him with a permanent limp. The captain, John Sullivan, suffers from a secret fear of responsibility after logging thousands of hours looking after the lives of passengers and aircrew. Young second officer Hobie Wheeler and veteran navigator Lenny Wilby are contrasts in age and experience.
Meanwhile, flight attendant Spalding attends to her passengers, each with varying personal problems, including jaded former actress May Holst, unhappily married heiress Lydia Rice, aging beauty queen Sally McKee, and cheerful vacationer Ed Joseph. Spalding befriends the terminally ill Frank Briscoe, after being charmed by his pocket watch. A last-minute arrival, Humphrey Agnew, causes the aircrew concern with his odd behavior.
After a routine departure, the airliner experiences sporadic, sudden vibrations. Although the aircrew senses that something may be wrong with the propellers, they cannot locate a problem. When a vibration causes Spalding to burn her hand, Dan inspects the tail compartment but still finds nothing wrong.
After nightfall, as the airliner passes the point of no return, Agnew confronts fellow passenger Ken Childs, accusing him of having an affair with his wife. The men struggle and Agnew pulls out a pistol, intending to shoot Childs, but before he can do so, the airliner swerves violently when it loses a propeller and its engine catches fire. The crew quickly extinguishes the fire, but the engine has twisted off its mounting. In mid-ocean, the aircrew radios for help and sets in motion a rescue operation. Dan discovers that the airliner is now losing fuel from additional damage to a wing tank. That, combined with adverse winds and the increased drag of the damaged engine, means that the airliner will eventually run out of fuel and be forced to ditch.
Unassuming José Locota disarms Agnew and confiscates the pistol, compelling him to sit quietly. Gustave Pardee, who up until now has made no secret of his fear of flying, inspires calm in his terrified fellow passengers. Dan calmly explains the situation, trying to lessen their anxiety, but warns that their chances of making the coast are "one in a thousand". The passengers rally around each other and find changed perspectives about their existing problems. They toss luggage from the airliner to lighten its weight, with May Holst literally kissing her mink coat goodbye.
In San Francisco, Manager Tim Garfield comes to the airline's operations center but has little hopes for the airliner's chances. A favorable change in the winds raises the crew's hopes that they have just enough fuel to reach San Francisco, but Wilby discovers that he made an elementary error in navigation and their actual remaining time in the air remains inadequate.
Dan's experience tells him that their luck would be better trying to make land than ditching in rough seas at night. Sullivan panics and prepares to ditch immediately, but Dan slaps him back to his senses. Thinking clearly again, Sullivan decides against ditching. As the airliner approaches rain-swept, night time San Francisco at a perilously low altitude, the airport prepares for an emergency instrument landing. The airliner narrowly surmounts the city's hills and breaks out of the clouds with the runway lights dead ahead, guiding them to a safe landing. As the passengers disembark, Garfield watches their reactions as they are harried by reporters. After the tumult dies down, he joins the aircrew inspecting their damaged engine and informs Dan that only 30 gallons of fuel remained in their tanks. Dan acknowledges the gamble they took and walks away, limping and whistling into the night. "So long ... you ancient pelican", Garfield mutters to himself.