With little notice, major U.S. airlines are working to adjust schedules after the Federal Aviation Administration ordered flight reductions at major airports starting Friday, Nov. 7, due to a shortage of air traffic controllers amid the longest government shutdown in history.

Transportation Secretary Sean Duffy announced a 10% flight cut at 40 airports, including New York, Los Angeles and Chicago, affecting both commercial and cargo service.

"This isn’t about politics – it’s about assessing the data and alleviating building risk in the system as controllers continue to work without pay," Duffy said in a statement accompanying the order. “It’s safe to fly today, and it will continue to be safe to fly next week because of the proactive actions we are taking.”

FAA Administrator Bryan Bedford told CEOs of major airlines that the cuts would start at 4% on Nov. 7, rising to 5% on Nov. 8 and 6% on Nov. 9, before hitting 10% next week.

Air traffic controllers and many other FAA employees are considered essential workers, meaning they are required to report for duty despite not receiving a paycheck during the government shutdown.

While employees at both agencies are expected to receive back pay for the duties they performed once the shutdown ends, many advocates say going weeks without pay puts them under additional stress and can force them to find other ways to earn temporary income.

Here's what airlines have said about how federal restrictions will impact flights.

United says cuts impact 'fewer than 200 flights' on first day

United Airlines said the restrictions would impact "fewer than 200 flights" on Friday, Nov. 7, according to an email statement to USA TODAY on Nov. 6. Cancellations will continue throughout the weekend, with approximately 4% of United flights being canceled on Saturday, Nov. 8 and Sunday, Nov. 9.

CEO Scott Kirby outlined the types of flights that may be reduced in a Nov. 5 memo to employees provided to USA TODAY, saying that domestic flights that do not operate between the airline's hubs and "regional flying" are on the chopping block. The memo also mentioned that United will offer about 4,000 flights per day.

United's CEO promised refunds to customers who did not want to fly during the flight restrictions. Kirby wrote that any customer is eligible for a refund while the reductions are in effect, "even if their flight isn't impacted." The offer includes non-refundable and basic economy tickets.

American Airlines says 220 flights cut

American Airlines announced it will cut about 220 flights each day from Friday, Nov. 7 through Monday, Nov. 10 in a statement provided to USA TODAY on Nov. 6. The airline said it represents 4% of flights at affected airports.

The company issued a travel waiver for the reduction period and said that customers who wish to change or cancel their flight can do so “without penalty.”

It said in a previous statement that it expects “the vast majority” of its customers to be unaffected and added Nov. 6 that it plans to operate around 6,000 daily flights following the cancellations.

Delta says it will operate 'vast majority' of system

Delta Air Lines said in a statement on Nov. 6 that it is operating the "vast majority" of its schedule, though it noted "frequency may be affected.”

The Atlanta-based airline said it expects to cancel approximately 170 flights on Friday, Nov. 7, across both Delta and Delta Connection services. Saturday, Nov. 8, should see fewer cancellations, the airline said, because demand and daily departures are typically lower on weekends. Delta operates about 5,000 flights a day system-wide.

The airline said it is treating the reductions similarly to how it would handle weather-related events to minimize last-minute disruptions. It plans to cancel flights a day in advance to reduce crowding and prevent day-of-travel surprises.

A travel waiver is now in place, offering customers additional flexibility to rebook without change fees.

Southwest says its cutting flights at 34 airports

Southwest Airlines said it is cutting about 120 flights across 34 airports on Nov. 7, according to a statement to USA TODAY. It added that it expects cancellations to be "less than 100 flights" on Nov. 8 and that "the vast majority of our Customers’ (sic) flights will not be disrupted."

Travelers with flights booked through Nov. 12 may choose to adjust their travel plans at no cost or receive a refund if they choose not to travel, even if their flight is not affected, the company said.

Reuters contributed to the reporting of this story.

This article originally appeared on USA TODAY: FAA orders US airlines to reduce service. Is your flight impacted?

Reporting by James Powel and Kathleen Wong, USA TODAY / USA TODAY

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