After two years of pandemic turndown, travel is making a big comeback (especially European travel). But airports and airlines aren’t quite ready for it. In the most recent example of flight frenzy overload, Heathrow International Airport in the U.K. has opted to cap departing passenger slots at 100,000 per day through the rest of the summer. The announcement came in an open letter from the airport’s CEO, John Holland-Kaye.

“Our assessment is that the maximum number of daily departing passengers that airlines, airline ground handlers and the airport can collectively serve over the summer is no more than 100,000,” he wrote. “We are asking our airline partners to stop selling summer tickets to limit the impact on passengers.”

The airport is routinely ranked as one of the busiest in the world. Factors like staff and security shortages and shuttered terminals led Heathrow to begin requesting that airlines cancel flights on short notice earlier this month. However, the new letter makes it clear that airlines weren’t voluntarily doing enough to respond to that request. “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. We have therefore made the difficult decision to introduce a capacity cap with effect from 12 July to 11 September,” wrote Holland-Kaye.

According to the letter, daily scheduled departing seats over that time period already exceed the cap, averaging about 104,000. And about 1,500 of those excess seats have already been sold to would-be-travelers. An airport spokesperson said that the capacity limit would be enforced by an independent contractor, Airport Coordination Limited, and that how individual airlines get their flight schedule within the new limit will be up to them, reported the New York Times.

Heathrow is far from the only airport that’s begun putting new travel capacity limits in place and cancelling flights. In the U.S. too, airports and airlines have been running ragged. Cancellations have been rampant, and new policies are popping up to incentivize people to reschedule travel and spend less time in airports. However, the biggest disruptions have been in Europe.

Charles de Gaulle airport in Paris, France, for instance, also cancelled flights en masse this month in response to labor disputes and a strike which only ended on Monday. Gatwick, another U.K. airport, instituted a max number of flights per day for July and August. Amsterdam’s Schiphol airport previously set its own new maximum capacity levels in June. Lufthansa cancelled more than 3,000 flights.

Outside of the airport, new travel restrictions and policies meant to limit European tourist takeovers are also emerging. Venice announced a reservation and fee system for visiting the historic city earlier this month. Daytrip tourists will have to pay a small fee ranging from about $3 to $10 dollars, and book their visit online. Those rules will go into effect in January 2023.

After years stuck largely at home, people are understandably hankering for a vacation. But to avoid entering the chaos, it might make sense to skip crossing the pond for a little while longer.