London Heathrow is imposing a two-month cap on daily passenger traffic to contain flight chaos, a dramatic response by the UK’s busiest airport to address the struggle with surging demand for travel.

The airport will limit daily passenger traffic to 100,000 departing people through September 11, asking carriers to refrain from selling tickets for that time. Current forecasts are modelling for as many as 104,000 passengers a day over the Northern Hemisphere summer, still below the roughly 125,000 this time before the pandemic.

The move comes in reaction to staffing that Heathrow said is not yet “up to full speed” as it rushed to replenish its workforce with new recruits. Some key functions, like ground handlers for baggage, remain significantly under-resourced, according to the airport. The hub has been particularly hard hit by the travel disruptions, as a surge in bookings during the busiest time of the year clashed with a mass exodus of workers during the pandemic.

“Our objective is to protect flights for the vast majority of passengers at Heathrow this summer,” chief executive officer John Holland-Kaye said in a release. “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.”

Ticket pricing and cancellation data show that Europe is where the turmoil is inflicting maximum pain on consumers, while Asia’s travel industry is still navigating COVID-19 and the US suffers from a shortage of pilots. Some airlines have already responded, with British Airways scrapping a swath of flights for the summer season. Heathrow said that of the expected 4000 excess daily seats, only about 1500 have currently been sold, giving it room to act.

‘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.’

Heathrow Chief Executive Officer John Holland-Kaye

While Heathrow was spared some of the Easter chaos, when images of long lines snaking out of airport buildings grabbed headlines, the hub has struggled in recent weeks as long-haul travel, in which the international hub specialises, comes rushing back. As a result, baggage has piled up outside terminals due to a shortage of luggage loaders.

Industry group Airlines UK, which counts British Airways and Virgin Atlantic as members, was unsympathetic to Heathrow’s decision.

“It is disappointing that Heathrow, which was forecasting lower passenger numbers and resources required during the recovery phase, has considered it necessary to take this action now to manage these shortcomings,” CEO Tim Alderslade said in an email. “The vast majority of flights from Heathrow are departing as planned this summer, and carriers will be in contact as early as possible with any customers affected by the cap.”