LONDON (AP) — Mideast carrier Emirates on Thursday rejected a demand by London’s Heathrow Airport for airlines to cut the number of passengers on summer flights in a bid to ease travel disruptions, calling it an “entirely unreasonable and unacceptable” move that shows “blatant disregard for customers.”

In a blistering statement, the airline accused Heathrow’s management of “incompetence” for not being ready to deal with the “super peak period” for travel. The airport says it’s been seeking help from airlines on solutions for months.

Emirates, one of the world’s biggest airlines, fired back a day after Heathrow announced it was capping daily passenger numbers at 100,000 and telling airlines to stop selling tickets as it seeks to quell travel chaos caused by soaring travel demand and staff shortages.

Airlines have already slashed thousands of flights from their summer schedules after U.K. aviation authorities, in a bid to prevent last-minute cancellations, said carriers wouldn’t be punished for not using valuable takeoff and landing slots.

Heathrow, Britain’s busiest airport, said the cuts weren’t enough, but Emirates drew a line, exposing tensions between the airport and the airlines that are its customers.

The problems have emerged around Europe. Booming demand for summer travel after two years of COVID-19 travel restrictions have swamped airlines and airports, which are shorthanded after many pilots, cabin crew, check-in staff, and baggage handlers were laid off. That’s left travelers facing last-minute cancellations, lengthy delays, lost luggage or long waits for bags.

Emirates, which operates six daily return flights between Heathrow and Dubai, United Arab Emirates, said it’s “highly regrettable” that the airport on Wednesday night gave it 36 hours to comply with capacity cuts “of a figure that appears to be plucked from thin air.”

“Their communications not only dictated the specific flights on which we should throw out paying passengers, but also threatened legal action for non-compliance,” the airline said.

Other airlines also grumbled. British Airways, which has the biggest presence at Heathrow and has already cut 11% of its scheduled flights through October, said the restrictions were “incredibly disappointing” and that it would cancel “a small number of additional flights.”

Heathrow blames a shortage of ground staff, which are contracted by airlines to check-in passengers, load and unload bags, and prepare aircraft for their next journey.

Emirates, however, said its ground-handling and catering services are owned by its parent company and “are fully ready and capable of handling our flights.” Blame instead lies with the airport’s “central services and systems,” it said.

The airline accused Heathrow management of being “cavalier” about travelers and airlines, with signs of a strong travel rebound apparent for months. Emirates said it got ready, including rehiring and training 1,000 pilots in the past year but that Heathrow failed to act, plan or invest.

“Now faced with an `airmageddon’ situation due to their incompetence and non-action, they are pushing the entire burden — of costs and the scramble to sort the mess — to airlines and travelers,” the statement said.

In response, Heathrow said it has been asking airlines for months to help draw up a plan to solve their staffing challenges, “but no clear plans were forthcoming, and with each passing day, the problem got worse.”

“We had no choice but to take the difficult decision to impose a capacity cap designed to give passengers a better, more reliable journey and to keep everyone working at the airport safe,” Heathrow said. “It would be disappointing if instead of working together, any airline would want to put profit ahead a safe and reliable passenger journey.”

Rebooking so many potentially affected passengers is impossible because all flights for the next few weeks are full, including at other London airports and on other airlines, Emirates said. Moving some operations to other U.K. airports at short notice is also unrealistic, it said.

Elsewhere in Europe, Germany’s Lufthansa said this week that it’s cutting 2,000 more flights in Frankfurt and Munich, mostly at peak times in the afternoon and evening over the next week, on top of 770 flights it axed from July 8 to 14.

More scheduled flight cancellations in August “are possible at a later date,” the airline said.

London’s Gatwick and Amsterdam’s Schiphol airports also have limited daily flights or passenger numbers.