Tens of thousands of airline passengers faced disruption across the United States on Saturday as airlines grounded more than 1,300 flights for a second day.

The cancellations were ordered by the Federal Aviation Administration (FAA) as part of a mandate to cut air traffic because of the US government shutdown, which began on October 1.

What do we know about the cancellations?

The FAA begancutting flights on Friday, ordering a 4% reduction at 40 major airports across the country.

By Saturday, more than 1,300 flights had been canceled, and over 5,000 were delayed nationwide, Reuters news agency reported.

Charlotte Douglas International Airport in North Carolina saw the highest number of cancellations, with 130 flights grounded by mid-afternoon.

Other major hubs — including Atlanta, the busiest airport in the US, as well as Chicago, Denver, and Newark — also experienced delays and cancellations.

Reagan National Airport in Washington, DC, was hit especially hard on Friday, with 18% of its arrivals canceled, NBC News reported.

Officials warned that even if the shutdown ends, air traffic operations won’t return to normal immediately.

Why is the US government shutdown affecting flights?

Over the past 39 days of shutdown, some federal employees have been temporarily furloughed, while others remain on the job without pay.

Air traffic controllers and many airport security screeners are federal employees, which is why the aviationsector has been hit especially hard, due to ongoing staffing shortages in radar centers and control towers at airports.

Many staff are working without pay, some are calling in sick, while others are taking second jobs to cover basic expenses after going more than a month without a paycheck.

Officials say between 20% and 40% of workers are not showing up on any given day.

In total, about 13,000 air traffic controllers and 50,000 airport screeners are still reporting to work without pay. Many were recently told they won’t receive another paycheck next week.

Despite the financial strain, the National Air Traffic Controllers Association said most controllers are continuing to work six days a week to keep flights moving.

Will the cancellations get worse?

The FAA has warned that flight cuts will increase to 6% on Tuesday, 8% on Thursday and 10% by Friday at major airports, depending on staffing levels.

US Transportation Secretary Sean Duffy said even deeper cuts may be needed. If more air traffic controllers call in sick or stop reporting to work, the FAA could reduce up to 20% of flights nationwide.

While many passengers have been able to rebook so far, experts say the situation could worsen quickly.

The Thanksgiving travel rush begins in less than three weeks, and even small disruptions could snowball into major delays and cancellations.

What's the latest on the US government shutdown?

US President Donald Trump's administration is urging Congress to pass a funding bill to reopen the government. Democrats say Republicans are responsible for the shutdown because they refuse to negotiate over extending health insurance subsidies.

But the impact of the record-breaking government shutdown may stretch far beyond airports. Nearly half of US air cargo is shipped in the bellies of passenger planes. If flight cancellations continue, shipping costs could rise and affect prices in stores.

Edited by: Roshni Majumdar