U.S. air traffic could slow to a trickle due to continuing federal government shutdown, warns Transportation Secretary Sean Duffy.

Recent orders from the Federal Aviation Administration (FAA) have led to notable flight cuts at top airports, driven by a lack of paid air traffic controllers who are reportedly not showing up for work. Starting last Friday, flights were reduced by 4%, expected to rise to 10% by November 14.

As of Sunday, over 1,700 flights were canceled and nearly 5,000 delayed, increasing travelers' frustrations ahead of the Thanksgiving holiday.

Duffy emphasized that if the shutdown persists, air travel will experience heavy disruption as controller availability diminishes. He mentioned that the significant staffing shortage has led to longer delays for passengers, notably at Newark and LaGuardia airports, with departure delays reaching 75 minutes on average.

The longer controllers go unpaid, the more are leaving the job, resulting in further flight cancellations and delays, Duffy said on a recent news program. He highlighted the importance of restoring staff and pay to prevent future complications.

With a lack of available air traffic controllers already notable, including retirements, Duffy warns of an uncertain outlook for air travel quality as travelers gear up for the holiday season. There are going to be a lot of angry Americans if this doesn’t change soon, he added.

According to Airlines for America, over 4 million passengers have been disrupted due to controller shortages since October 1. As the government shutdown continues, Duffy indicated that the federal situation will likely worsen before improving.