The plot unfolds during a long and tumultuous night at Lincoln International, a fictional airport in Chicago, as it faces a sudden and intense blizzard. The central character, Mel Bakersfeld (Burt Lancaster), serves as the airport general manager, whose unwavering commitment to his role is wreaking havoc on his personal life. His wife, Cindy (Dana Wynter), is increasingly resentful of his priorities, feeling overshadowed by Mel's dedication to his job, which she perceives as an excuse to dodge the social engagements she desperately wants him to attend as she attempts to ascend the social ladder among Chicago's elite.
As tensions within his marriage escalate, Mel finds solace in the company of Tanya Livingston (Jean Seberg), a charming divorcee and Trans America Airlines' passenger relations manager, complicating his already strained home life. The narrative revolves around Mel's attempts to keep the airport operational amid the raging snowstorm. A critical issue arises with the unexpected closure of primary runway 29, as a landing aircraft misjudges its turn and gets stuck in the snow, rendering it unreachable.
In this moment of crisis, Mel turns to Joe Patroni (George Kennedy), the hard-headed head of maintenance for Trans World Airlines. Tasked with unblocking the situation, Patroni must rally his team to dig out the aircraft while negotiating the stubborn pilots who hesitate to act for fear of damaging the plane. Meanwhile, Mel also navigates personal tensions with his brother-in-law, Vern Demerest (Dean Martin), a self-assured senior pilot for Trans Global Airlines. Unbeknownst to Mel, Vern is embroiled in an affair with Gwen Meighen (Jacqueline Bisset), a chief stewardess meant to be on a flight to Rome.
As the crisis at the airport deepens with the diversion of flights to the shorter runway 22—which leads to protests from frustrated residents—Mel stubbornly insists that operations must continue despite pressures to shut down. An unexpected turn of events occurs when they arrest Mrs. Ada Quonsett (Helen Hayes), an elderly stowaway with a knack for sneaking onto flights, adding a humorous layer to the dire situation.
Amidst the chaos, we meet D.O. Guerrero (Van Heflin), a distraught contractor with devastating plans—he's built a bomb to end his life by detonating a plane over the ocean, ensuring that his wife can claim his life insurance. As Guerrero boards the plane, tensions rise for the passengers, particularly as his wife, Inez (Maureen Stapleton), rushes to the airport unaware of his intentions. As the drama unfolds mid-flight, chaos ensues when the passengers discover the threat Guerrero poses, leading to a nail-biting sequence of events that culminate in an explosion aboard the plane, endangering all on board.
With time running out and the conditions worsening, the pilots, led by Vern, discover that runway 22 is insufficient for landing the damaged aircraft. The crisis escalates as Mel and Patroni scramble to remedy the blockage on runway 29, allowing for a precarious landing where every moment counts. Ultimately, the film concludes with a mix of personal revelations and rescue, as Mel and Tanya explore new beginnings together, leaving behind the remnants of Mel's personal struggles while Inez grapples with the emotional fallout of the events at Lincoln International.
