Emirates airline criticized London Heathrow on Thursday, one of the busiest international airports in the world, claiming its “incompetence” in planning for a particularly busy summer travel season will effectively cause it to “throw out paying passengers.” 

“[Heathrow] chose not to act, not to plan, not to invest,” Emirates said in a press release. “Now faced with an ‘airmageddon’ situation due to their incompetence and nonaction, they are pushing the entire burden—of costs and the scramble to sort the mess—to airlines and travelers.”

The flagship carrier from the Middle East voiced its concerns after airport officials issued a request to keep the number of daily travelers at 100,000. Heathrow currently forecasts an average of 104,000 daily passengers. It says that of the extra 4,000 tickets expected, only about 1,500 have been sold. It is requesting that the remaining 2,500 tickets not be sold in order to “limit the impact on customers.” 

“We recognize that this will mean some summer journeys will either be moved to another day, another airport or be canceled, and we apologize to those whose travel plans are affected,” a Heathrow spokesperson told Fortune in an email. “But this is the right thing to do to provide a better, more reliable journey and to keep everyone working at the airport safe.”

The airport also specified that the “vast majority of passengers” traveling through Heathrow this summer would not be affected by the travel cap. 

Emirates explained that some of the logistical challenges were simply too complex to be solved within the 36-hour timetable London Heathrow provided. 

“Moving some of our passenger operations to other U.K. airports at such short notice is also not realistic,” the airline said in a public statement. “Ensuring ground readiness to handle and turnaround a wide-body long-haul aircraft with 500 passengers on board is not as simple as finding a parking spot at a mall.”

Emirates did not immediately respond to Fortune’s request for comment.

The key hurdle that both airport personnel and airlines face this summer is staffing for ground control operations. The Heathrow spokesperson said that current staffing levels for ground teams are at 70% of pre-pandemic levels while travel demand has returned to 80% to 85%. 

“For months we have asked airlines to help come up with a plan to solve their resourcing challenges, but no clear plans were forthcoming, and with each passing day the problem got worse,” the Heathrow spokesperson explained.  

Emirates countered Heathrow’s claim, saying its ground handling team is “fully ready and capable of handling our flights.” Instead, it blamed airport personnel for their inability to handle “central services and systems” such as security checks and transportation between terminals. 

One of the principal questions facing the airlines, the airport, and perhaps most important, passengers is what will happen to passengers whose flights are delayed, rerouted, or canceled. Airlines are concerned about losing ticket sales, especially after a pandemic-induced decline in the past two years, and the brand implications of a negative consumer experience. Airports argue that any delays or cancellations should be treated as the responsibility of the airlines. 

“Airlines will decide how to respond to these limits, and if there are any flight cancellations or changes to flight details, airlines will contact their passengers directly,” said the Heathrow spokesperson. “Airlines also have the option to simply stop selling vacant seats on existing flights to ensure passenger numbers do not grow.”