Heathrow airport has ordered airlines to stop selling tickets for summer flights as it imposes a cap on the number of passengers.
No more than 100,000 passengers are allowed daily from Tuesday until September 11, West London Airport announced.
Airlines planned to operate flights with an average daily capacity of 104,000 seats during that period, according to Heathrow.
That figure was much higher before airlines such as British Airways canceled thousands of flights due to disruptions in the aviation sector.
Around 131,000 passengers departed on August 4, 2019, Heathrow’s busiest day on record.
The cap will lead to more cancellations, but passengers will not be entitled to compensation from airlines as the cause will be classified as beyond their control.
Some airlines may choose to operate flights with empty seats.
Skyrocketing airfares will rise further as the number of available seats shrinks further.
In recent months, many passengers have faced long queues and have been unable to bring their luggage onto their flights.
Airlines were able to take advantage of a government scheme that meant they had until July 8 to cancel summer flights without losing their future rights to valuable takeoff and landing slots.
Some airlines took “significant action” but “others have not,” according to Heathrow chief executive John Holland-Kaye.
In an open letter to passengers, he wrote: “Further action is needed now to ensure passengers have a safe and reliable journey.
“Our assessment is that the maximum number of daily departing passengers that airlines, airline ground handlers and the airport can collectively serve during the summer is no more than 100,000.
“The latest forecasts indicate that, even despite the amnesty, daily exit seats during the summer will average 104,000, giving a daily excess of 4,000 seats.
“On average, only around 1,500 of these 4,000 daily seats have currently been sold to passengers, so we are asking our partner airlines to stop selling summer tickets to limit the impact on passengers.”
Holland-Kaye admitted that there are “some critical functions at the airport that are still significantly under-resourced,” such as ground handling.
A Virgin Atlantic spokeswoman said the company is “ready to deliver its full schedule this summer”.
It continued: “However, we support the proactive steps Heathrow is taking to reduce disruptions, provided the proposed action does not disproportionately affect local carriers at the airport.
“Action must be based on a comprehensive analysis showing the most effective measures to improve the situation and keep customers moving.
“We look forward to seeing Heathrow’s comprehensive plan to return to normal operations as soon as possible.”
Guy Hobbs, acting editor of consumer magazine Which? Travel said: “Thousands of people will now worry that their flight or holiday plans are about to fall apart.
“Heathrow must work with airlines to provide clarity quickly on which flights are being cut, and airlines must be honest with affected passengers about their right to rebook as soon as possible, including services from other airlines.”
Tim Alderslade, chief executive of Airlines UK, the industry body representing UK registered airlines, said: “UK airlines are working around the clock to deliver resilient summer schedules and Heathrow must play its part. full on delivery to travelers.
“It is disappointing that Heathrow, which was forecasting lower passenger numbers and resource requirements during the recovery phase, has found it necessary to take this action now to manage these shortcomings.
“The vast majority of flights from Heathrow will depart as planned this summer, and airlines will contact customers affected by the limit as soon as possible.”
A response was sought from British Airways, Heathrow’s largest airline.