WASHINGTON – With the ongoing federal government shutdown showing no signs of resolution, Transportation Secretary Sean Duffy cautioned on Sunday that U.S. air traffic might dwindle significantly, especially as the bustling Thanksgiving travel season approaches.

Last week, the Federal Aviation Administration mandated a reduction in flights at the country’s major airports. This decision comes as some air traffic controllers, who have been without pay for nearly a month, are increasingly opting to stay home.

These flight reductions, which began at 4% last Friday, are set to escalate to 10% by November 14. The cutbacks are applicable from 6 a.m. to 10 p.m. local time and will affect all commercial flight operations.

According to FlightAware, an aviation tracking platform, by 10:30 a.m. Eastern time on Sunday, 1,375 flights had already been canceled, following over 1,500 cancellations the previous day.

Duffy has indicated that further reductions—potentially reaching 20%—could be necessary, especially if air traffic controllers miss a second consecutive paycheck.

“More controllers aren’t coming to work day by day, the further they go without a paycheck,” Duffy told “Fox News Sunday.”

And he prepared Americans for what they could face during the busy Thanksgiving holiday.

“As I look two weeks out, as we get closer to Thanksgiving travel, I think what’s going to happen is you’re going to have air travel slow to a trickle as everyone wants to travel to see their families,” Duffy said.

With “very few” controllers working, “you’ll have a few flights taking off and landing” and thousands of cancellations, he said.

“You’re going to have massive disruption. I think a lot of angry Americans. I think we have to be honest about where this is going. It doesn’t get better,” Duffy said. “It gets worse until these air traffic controllers are going to be paid.”

The government has been short of air traffic controllers for years, and multiple presidential administrations have tried to convince retirement-age controllers to remain on the job. Duffy said the shutdown has exacerbated the problem, leading some air traffic controllers to speed up their retirements.

“Up to 15 or 20 a day are retiring,” Duffy said on CNN.

Duffy said Defense Secretary Pete Hegseth texted him with an offer to lend military air traffic controllers, but it’s unclear whether the staff is certified to work on civilian systems.

Duffy denied Democratic charges that the flight cancellations are a political tactic, saying they were necessary due to increasing near-misses from an overtaxed system.

“I needed to take action to keep people safe,” Duffy said. “I’m doing what I can in a mess that Democrats have put in my lap.”