Heathrow Airport has introduced a cap on passenger numbers this summer as the aviation sector struggles to cope with demand for travel.
No more than 100,000 daily passengers will be able to depart from July 12 until September 11, the west London airport announced.
Airlines planned to operate flights with a daily capacity averaging 104,000 seats over that period, according to Heathrow.
The airport said it has ordered airlines to “stop selling summer tickets to limit the impact on passengers”.
The measure will lead to more cancellations on top of the thousands of flights axed in recent months.
British Airways, the largest airline at Heathrow, has been approached for a response.
Affected passengers will not be entitled to compensation as the reason for the cancellations will be classified as being outside the control of airlines.
Air fares are likely to increase further as the number of available seats is further cut.
Heathrow chief executive John Holland-Kaye said: “Over the past few weeks, as departing passenger numbers have regularly exceeded 100,000 a day, we have started to see periods when service drops to a level that is not acceptable.”
To give our passengers a better, more reliable service this summer and to keep our colleagues safe – we’ll be implementing a departing passenger cap of 100k from today to 11 Sept. Read more from our CEO about why we’re doing this here: https://t.co/kf3WdJeLbe pic.twitter.com/bJSlf3L95f
— Heathrow Airport (@HeathrowAirport) July 12, 2022
Problems include long queue times, delays for passengers requiring assistance, bags not travelling with passengers or arriving late, low punctuality and last-minute cancellations, Mr Holland-Kaye said.
He said this is due to a combination of poor punctuality of arrivals due to delays at other airports and in European airspace, as well as increased passenger numbers “starting to exceed the combined capacity of airlines, airline ground handlers and the airport”.
He added: “Our colleagues are going above and beyond to get as many passengers away as possible, but we cannot put them at risk for their own safety and wellbeing.”
Airlines were able to take advantage of a Government scheme which meant they could cancel summer flights without losing their future rights to the valuable take-off and landing slots.
But even with this measure, Heathrow believes airlines still planned to operate flights carrying 4,000 more daily passengers than could be processed in an acceptable manner.
The airport ordered airlines to cancel 61 flights at short notice on Monday to ease pressure after a failure of baggage systems over the weekend.
Heathrow said: “On average only about 1,500 of these 4,000 daily seats have currently been sold to passengers, and so we are asking our airline partners to stop selling summer tickets to limit the impact on passengers.
“We recognise that this will mean some summer journeys will either be moved to another day, another airport or be cancelled and we apologise to those whose travel plans are affected.
“But this is the right thing to do to provide a better, more reliable journey and to keep everyone working at the airport safe.”
Heathrow insisted the capacity cap is “in line with limits implemented at other airports”.
It added that airlines have “discretion as to how they implement this in their individual schedules”.
Some carriers may choose to operate flights with empty seats.