Baltimore-Washington International Thurgood Marshall Airport will see a 10% cut in flights as part of federal plans to slash airline capacity due to the government shutdown. So will Ronald Reagan Washington National and Washington Dulles International.

The Federal Aviation Administration is reducing air traffic by 10% across 40 “high-volume markets” starting this Friday, citing safety concerns and staffing shortages in air traffic controllers.

According to a list distributed to airlines and obtained by the Associated Press, the affected airports include the busiest ones across the U.S. — including Atlanta, Denver, Dallas, Orlando, Miami, and San Francisco. In some of the biggest cities — such as New York, Houston and Chicago — multiple airports will be affected. All three of the Maryland region’s major airports are on the list.

Nearly 500 flights scheduled for Friday were already cut nationwide, and the number of cancellations climbed throughout Thursday afternoon, according to FlightAware, a website that tracks flight disruptions.

That’s more than four times the number of flights canceled on Thursday.

The FAA is imposing the flight reductions to relieve pressure on air traffic controllers who are working without pay during the government shutdown and have been increasingly calling out of work. The longest government shutdown in U.S. history added pressure to a system that was already understaffed. There are currently fewer than 11,000 certified controllers, which is 3,000 short of the nationwide target, according to NPR.

“We just can’t ignore it,” Bryan Bedford, the agency’s administrator, told reporters at a press conference on Wednesday. “When the early indicators are telling us we can take action today to prevent things from deteriorating.”

Travelers should check flights with their airlines, advised BWI spokesperson Jonathan Dean, adding that people may experience cancellations and delays.

Southwest Airlines, which has a regional hub at BWI, is evaluating how air traffic cuts will impact its flights. The airline will automatically rebook canceled flights, and travelers can also ask for a refund, Southwest says on its website.

Around 650 flights arrive and depart from BWI on a daily basis, according to the airport. During the first month of the shutdown, the airport did not see “significant impact” on operations for the airlines or passengers, Dean said in an email on Oct. 31.

U.S. Rep. Kweisi Mfume, a Baltimore Democrat, agreed that airport safety is paramount but bemoaned the added burden the cuts will place on everyday Americans already dealing with the consequences of the federal government shutdown. He said he was not given advance notice of the changes, something he said has become common under the Trump administration.

“This is going to mean such a huge inconvenience to so many families that need and have to travel,” Mfume said.

Full list of airports affected

1. Anchorage International in Alaska

2. Hartsfield-Jackson Atlanta International in Georgia

3. Boston Logan International in Massachusetts

4. Baltimore-Washington International Thurgood Marshall in Maryland

5. Charlotte Douglas International in North Carolina

6. Cincinnati/Northern Kentucky International in Ohio

7. Dallas Love Field in Texas

8. Ronald Reagan Washington National in Virginia

9. Denver International in Colorado

10. Dallas/Fort Worth International in Texas

11. Detroit Metropolitan Wayne County in Michigan

12. Newark Liberty International in New Jersey

13. Fort Lauderdale/Hollywood International in Florida

14. Honolulu International in Hawaii

15. Houston William P. Hobby in Texas

16. Washington Dulles International in Virginia

17. George Bush Houston Intercontinental in Texas

18. Indianapolis International in Indiana

19. John F. Kennedy International in New York

20. Harry Reid International Airport in Las Vegas

21. Los Angeles International in California

22. LaGuardia Airport in New York

23. Orlando International in Florida

24. Chicago Midway International in Illinois

25. Memphis International in Tennessee

26. Miami International in Florida

27. Minneapolis/St Paul International in Minnesota

28. Oakland International in California

29. Ontario International in California

30. Chicago O`Hare International in Illinois

31. Portland International in Oregon

32. Philadelphia International in Pennsylvania

33. Phoenix Sky Harbor International in Arizona

34. San Diego International in California

35. Louisville International in Kentucky

36. Seattle/Tacoma International in Washington

37. San Francisco International in California

38. Salt Lake City International in Utah

39. Teterboro in New Jersey

40. Tampa International in Florida

Baltimore Banner reporter Brenda Wintrode and Associated Press reporters Josh Funk and Rio Yamat contributed to this report.