Travel chaos took a turn for the worse on Tuesday as airlines were asked to stop selling summer tickets.
According to a statement from the airport, it has introduced a cap on the number of passengers that can be flown each day.
"Some airlines have taken significant action, but others have not, and we believe that further action is needed now to ensure passengers have a safe and reliable journey," said John Holland- Kaye.
There will be a capacity cap in place from July to September.
Long lines, lost luggage, and flight delays have been caused by the high passenger numbers.
Over the summer, the maximum number of daily passengers can be 100,000, according to Holland- Kaye. Only 1,500 of the 4,000 daily seats have been sold so far, but the number of daily outbound seats will average 104,000 over the summer.
Holland- Kaye asked airlines to stop selling summer tickets to limit the impact on passengers.
"We can't put passengers at risk for their own safety and wellbeing because staff at the airport are putting all their effort into making sure passengers fly," he said.
Customers were told to arrive at the airport three hours before their departure time in case of long lines.
Some passengers at the airport only got a few hours notice of their canceled flights. Five of the British Airways flights were canceled and only one left on time.
One passenger told Insider that she was able to get her luggage back four days after she arrived at the airport, while three others said they had no idea where their luggage was.
In an investor report in June, the airport said that it expected to serve 54.4 million passengers in 2022, 9 million more than first forecast in December. By the end of May, it had surpassed the total number of passengers it served.
In May, the majority of passengers were through security in 10 minutes.