The Federal Aviation Administration was experiencing staffing issues or anticipating shortages at airports and other air traffic control facilities in the United States on Monday night.
Reports of the staffing shortfalls came hours after Transportation Secretary Sean Duffy said there has been a slight increase in sick calls since the government shutdown began on Wednesday.
No air traffic controllers were expected at the tower at Hollywood Burbank Airport in the Los Angeles area for hours Monday night because of staffing issues, a source familiar with the situation said.
The FAA’s website showed the staffing issue between 4 p.m. and 9:59 p.m. PT (7 pm. Monday to 12:59 a.m. Tuesday ET).
The source told NBC News that some air traffic will be handled by San Diego terminal radar approach control at a much reduced rate — meaning arrival and departure delays are certain.
A spokesperson for Hollywood Burbank Airport, a smaller airport in the Los Angeles area, did not immediately respond to a request for comment Monday.
The airport said Monday evening on X that it was still open.
"Operations are continuing at Hollywood Burbank Airport," it said. "Please check with your airline — before arriving at the airport — for updates on possible delays or cancellations."
Newark Liberty International Airport in New Jersey and Denver International Airport also experienced issues with air traffic control staffing Monday, according to the FAA’s website.
A reason for the staffing problem at Hollywood Burbank was not clear.
Because of the federal government shutdown, air traffic controllers were working without pay Monday.
The shutdown is set to hit the one-week mark after the Senate again failed to pass legislation Monday night that would reopen the government. With no negotiations taking place between Democrats and Republicans, there are no signs of a breakthrough on the horizon.
Duffy said earlier Monday that there has been an increase in sick calls since the government shut down and funding lapsed, but he said the increase was slight.
“So we’re tracking sick calls, sick leave, and have we had a slight tick up in sick calls? Yes, and then you’ll see delays that come from that,” Duffy told reporters at the Newark airport.
“Our priorities are safety. And so, if we have additional sick calls, we will reduce the flow consistent with a rate that’s safe for the American people,” he said.
An FAA spokesperson referred to Duffy's earlier comments when asked about staffing at Burbank on Monday evening.
"As Secretary Duffy said, there have been increased staffing shortages across the system. When that happens, the FAA slows traffic into some airports to ensure safe operations," the spokesperson said.
The National Air Traffic Controllers Association union pointed to a national shortage of air traffic controllers. Officials have warned about the shortage since before the government shut down.
"It is normal for a few air traffic controllers to call in sick on any given day, and this is the latest example of how fragile our aviation system is in the midst of a national shortage of these critical safety professionals," the union said.
