Terrence Rattigan's script for Anthony Asquith's The V.I.P.s (1963) was inspired by a true story which Vivian Leigh once told him about the time she decided to leave her husband, Laurence Olivier, for fellow actor Peter Finch. Leigh and Finch found themselves in the V.I.P. lounge at London's Heathrow Airport, about to run away together, when all flights were grounded by impenetrable fog. During the ensuing fog-bound hours, Leigh changed her mind.
[Ironically, plans to shoot several of the film's scenes at Heathrow's Terminal 3 (rather than on the set at MGM's Borehamwood Studios) had to be abandoned -- because of fog!]