Global airlines continued to tumble as investors worried that demand for flights through the U.K. could suffer following the country’s decision to leave the European Union.

EasyJet Plc fell the most in 12 years after warning that the U.K. vote will hurt earnings for the rest of the summer as travel demand wanes. In the U.S., United Continental Holdings Inc. posted its biggest two-day intraday decline in five years, while American Airlines Group Inc. and Delta Air Lines Inc. dropped the most since August.

U.S. airlines could take a hit if, as expected, Britons cut their trans-Atlantic travel because of a plummeting pound, although that could be partly offset if Americans cross the pond to take advantage of the dollar’s relative strength. Concern about the future of the U.S.’s market-access treaty with Europe also weighed on shares.

“The vote to leave the EU does create uncertainty with respect to near-term demand for air travel to/from the U.K., as well as how the U.K. will feature in a revised EU-U.S. Open Skies accord,” Deutsche Bank analyst Michael Linenberg said in a note on Monday. The three major US airlines devote 2.8 percent to 6.3 percent of their seating capacity to the U.K. market, so weak traffic on such flights could hurt earnings, he said.

London’s Standing

Shares of U.K.-based airlines took the biggest drubbing.

Luton, England-based EasyJet plunged 22 percent to close at 1,020 pence. Europe’s second-biggest discount carrier dropped 14 percent on Friday after the Brexit results were announced. International Consolidated Airlines Group SA declined 16 percent Monday after tumbling 23 percent Friday. The company’s British Airways unit is particularly exposed to any impact that leaving the EU will have on London’s standing as a financial center.

In the U.S., United fell 7.9 percent to $37.83 at 1:41 p.m. in New York, and tumbled as much as 17 percent since Friday morning, the most intraday since February 2011. American dropped as much as 18 percent for the two days, while Delta tumbled as much as 15 percent. The Atlanta-based carrier recorded a higher average fare per mile on trans-Atlantic routes last year than for any other region outside the U.S., according to data compiled by Bloomberg.

Taking Time

“It will take time for this to play out, but we suspect the U.K. will need to renegotiate bilateral agreements with the EU,” Cowen & Co. analyst Helane Becker said in a note. “We expect airlines to reduce capacity to the U.K. as U.K. outbound traffic is likely to decline by as much as 5 percent,” she wrote, citing a recent study by the International Air Transport Association industry group.

U.S. carriers that focus primarily on the domestic market performed better than global carriers since the Brexit vote. Southwest Airlines Co. dropped 7 percent over the two days, while Spirit Airlines Inc. fell 6.4 percent.

“We expect Brexit-related uncertainty to continue to weigh on network carriers, and reiterate our confidence in domestic carriers,” according to Credit Suisse analyst Julie Yates, who said the sell-off for American Airlines may have been overdone Friday.

©2016 Bloomberg L.P.

This article was written by Michael Sasso from Bloomberg and was legally licensed through the NewsCred publisher network.

Photo Credit: EasyJet's stocks fell the furthest they have in 12 years following Brexit vote. EasyJet