As Storm Ciara sweeps in from the Atlantic, bringing winds of up to 100mph, airline schedules have been drastically cut.
The “flow rate” at Heathrow airport, which is expecting severe crosswinds, has been reduced, with commensurate cancellations.
The Independent calculates around 25,000 passengers have been hit by cancellations to and from Heathrow.
British Airways’ passengers are worst affected. The airline has cancelled at least 140 flights to and from Heathrow, including nine long-haul round-trips.
BA has grounded services to Dallas-Fort Worth, Dubai, Las Vegas, Los Angeles, Miami, New York JFK, Philadelphia, San Diego and Vancouver. The move will affect about 5,000 passengers.
In addition many short-haul trips have been axed, with a dozen Amsterdam flights and 10 between Heathrow and Edinburgh cancelled.
Barcelona, Dublin, Dusseldorf, Frankfurt, Nice and Paris also face multiple cancellations.
Among domestic links, Aberdeen, Glasgow, Inverness, Leeds Bradford and Manchester have had flights cut.
A spokesperson for British Airways said: “Like all airlines operating in to and out of the UK tomorrow, we will be affected by Storm Ciara.
“Safety is at the heart of everything we do, so we’re merging a number of flights to avoid operating when the winds are at their strongest.
“We’re doing everything we can to minimise disruption, including offering those who are booked on any short haul services tomorrow a range of flexible rebooking options.”
Other airlines have made multiple cancellations of Heathrow flights, including Aer Lingus to Cork, Dublin and Shannon; KLM to Amsterdam; Lufthansa to Frankfurt and Munich.
United has cancelled its overnight inbound arrival from Chicago, and the outbound service. In addition, an Emirates flight from Dubai to Heathrow and back has been cancelled.
At Gatwick airport, the busiest single-runway airport in the world, the only cancellations so far are on British Airways to and from Cologne, Jersey, Malaga and Milan.
London City airport has many cancellations for Sunday afternoon. The British Airways business class only link to New York is grounded, along with KLM flights to and from Amsterdam, Lufthansa to and from Frankfurt and Swiss to and from Zurich.