Thousands of flights have been delayed or canceled across the country as Americans face another day of travel uncertainty.

Duffy spoke as a federal government shutdown was into its 40th day in Washington, D.C., where senators were set to convene for a rare Sunday session as negotiations in the upper chamber drag on. Neither side appears close to backing down, as Democrats and Republicans battle over expiring subsidies for the Affordable Care Act's healthcare exchanges.

An advisory on the Federal Aviation Administration website that tracks flight delays across the country warns that those delay times are "increasing" in Newark.

Transportation Secretary Sean Duffy said that there will be a 10% reduction in flights at 40 major airports if the government shutdown continues.

Rep. Nicholas Begich warns Alaska's rural villages face supply shortages as government shutdown reduces flight capacity at major cargo hub airports.

On Tuesday, Department of Transportation (DOT) Secretary Sean Duffy threatened to close airspace across portions of the United States unless Democrats agreed to end the standoff over the government shutdown.

Democratic Party senators were split on why they think Transportation Secretary Sean Duffy called for a 10% reduction in air traffic ahead of Thanksgiving.