Flights departing for Los Angeles International Airport were halted briefly due to a staffing shortage at a Southern California air traffic facility, the Federal Aviation Administration said Sunday, when the agency also reported staffing-related delays in Chicago, Washington and Newark, New Jersey.

The FAA issued a temporary ground stop at one of the world’s busiest airports soon after U.S. Transportation Secretary Sean Duffy predicted that travelers would see more flights delayed and canceled in the coming days as the nation’s air traffic controllers work without pay during the federal government shutdown.

During an appearance on the Fox News program “Sunday Morning Futures,” Duffy said more controllers were calling in sick as money worries compound the stress of an already challenging job.

“Just yesterday, ... we had 22 staffing triggers. That’s one of the highest that we have seen in the system since the shutdown began. And that’s a sign that the controllers are wearing thin,” he said.

The FAA said planes headed for Los Angeles were held at their originating airports starting at 11:42 a.m. Eastern time, and the agency lifted the ground stop at 1:30 p.m. Eastern time.

The hold did not appear to cause continuing problems at LAX; according to flight tracking website FlightAware, Dallas Fort Worth International Airport and Dallas Love Field Airport saw a much bigger share of late arrivals due to what the FAA said were weather and equipment issues.

Too few air traffic controllers per shift also caused takeoff and arrival disruptions Sunday at New Jersey’s Newark Liberty International Airport and Teteboro Airport, and at Southwest Florida International Airport in Fort Meyers, Florida, according to the FAA.

On Sunday evening, the FAA also slowed traffic into Ronald Reagan Washington National Airport and Chicago O’Hare International Airport because of traffic controller staffing.