All flights into and out of one of the United States’ busiest runways were halted for a time Tuesday due to a bomb threat, federal authorities announced.

The Federal Aviation Administration plans to cut flights by 10 percent at 40 airports—including Reagan National, Dulles, and BWI—starting Nov. 7 if the government shutdown continues. The move aims to ease strain on unpaid air traffic controllers but is expected to cause widespread delays and cancellations in the Washington area and nationwide.

Major airlines braced for a third day of government-mandated flight cuts Sunday after rising air traffic control staffing shortages snarled thousands of flights on Saturday.

“You can’t expect people to go in to work when they’re not getting a paycheck,” said Kelly Matthews of Flat Rock, Michigan, a frequent business traveler who has canceled most of her upcoming trips.