Transportation Secretary Sean Duffy warned Tuesday that the ongoing government shutdown could trigger severe disruptions in air travel if it continues long enough for air traffic controllers to miss another paycheck.

Airports across the country have already experienced significant delays — some lasting several hours — as the Federal Aviation Administration (FAA) periodically slows or halts air traffic due to staffing shortages. Last weekend brought some of the worst impacts, with prolonged delays at Newark Liberty International Airport in New Jersey.

Duffy and leaders of the air traffic controllers union cautioned that conditions will deteriorate further as the shutdown drags on and employees continue working without pay. FAA staff missed their first paycheck on Oct. 28, and their next one is due next Tuesday.

“Many controllers said, ‘We can handle missing one paycheck — not all of us, but many. But none of us can go without two,’” Duffy said. “If we reach next week, Democrats, you will see mass chaos — widespread delays, cancellations, and possibly even airspace closures because we simply won’t have enough controllers to manage traffic.”

So far, flight disruptions during the shutdown have been mostly isolated and short-term, but a broader, systemwide slowdown could build pressure on Congress to strike a deal. Experts warn that if controllers miss another paycheck, the situation could worsen rapidly, especially if groups of them start calling in sick in protest — something both Duffy and the National Air Traffic Controllers Association have urged against.

Mike McCormick, a former FAA air traffic control manager and current professor at Embry-Riddle Aeronautical University, explained that temporarily closing sections of airspace is a routine measure during major storms or when staffing levels drop too low at radar centers. Such closures function similarly to the ground delay programs the FAA uses at airports facing staff or equipment shortages.

Major airlines, aviation unions, and travel industry groups are pushing Congress to end the shutdown by approving a clean funding resolution supported by Republicans.

The U.S. Travel Association warned in a letter to Congress that the shutdown has already cost the economy over $4 billion and that losses could escalate if it continues into the Thanksgiving travel rush.

“With Thanksgiving — the busiest travel period of the year — fast approaching, the consequences of a prolonged shutdown will be immediate, deeply felt by millions of travelers, and economically devastating for communities nationwide,” the association said.

Typically, airlines aim for at least 80% of flights to depart and arrive within 15 minutes of schedule. According to aviation data firm Cirium, since the shutdown began Oct. 1, overall performance has stayed near that benchmark, though Sunday saw only 56% of flights leaving Newark on time and 70% in Orlando.

As of midday Tuesday, FlightAware reported 1,932 flight delays across the U.S. — slightly below average — though the FAA noted staffing shortages were affecting flights in Phoenix, while strong winds were causing delays at Newark and LaGuardia airports.