Major US airlines, including United, Southwest, and Delta, have begun canceling flights after the Federal Aviation Administration (FAA) ordered reductions in air traffic at 40 major airports, citing safety concerns linked to the ongoing government shutdown.

The Associated Press reported that regulators identified “high-volume markets” where traffic must be reduced by 4% starting 6 am ET on Friday. The measure is expected to trigger thousands of cancellations and ripple through schedules nationwide. While space launches will also face restrictions, international routes will be spared.

Delta said Thursday it would cancel 170 flights on Friday and fewer on Saturday, calling it a “lighter travel day.” Southwest plans to scrap 120 flights, while United expects to cut 4% of its operations from Friday through Sunday.

The FAA said the flight reductions aim to maintain safety standards as the federal shutdown drags into its 37th day, the longest in US history, with no breakthrough between Republicans and Democrats on the budget standoff.

According to aviation analytics firm Cirium, the 4% cut could mean up to 1,800 flight cancellations and as many as 268,000 lost seats.

Washington-area airports hit hard

All three major airports serving the US capital, Dulles, Baltimore/Washington International, and Reagan National, will be affected, causing expected delays for lawmakers and travelers alike.

United CEO Scott Kirby said the regulator’s goal “is to relieve pressure on the aviation system so that we can all continue to operate safely,” adding that “safety remains the FAA’s highest priority, and ours as well.” Kirby said United would make “rolling updates to our schedule” to give passengers advance notice and minimize disruption.

Delta said it would “operate the vast majority” of flights as planned, especially long-haul international routes, while offering flexible rebooking and cancellation options “without penalty".

Mounting pressure before Thanksgiving

The FAA’s directive begins with a 4% cut on Friday and could rise to 10%, ABC News reported. The timing, just two weeks before Thanksgiving, America’s busiest travel period, has intensified calls for Congress to resolve the shutdown.

Transportation Secretary Sean Duffy said controllers, many working unpaid since October 1, were under mounting strain. “A lot of us can navigate missing one paycheck. None of us can manage missing two,” he said, warning Democrats would bear responsibility for any “mass chaos” that followed.

American Airlines said most customers would not be affected and long-haul flights would operate normally, but urged “leaders in Washington to reach an immediate resolution to end the shutdown.” The airline also thanked federal employees “working right now without pay.”

FAA Administrator Bryan Bedford said the flight cuts were “unprecedented” in his 35-year career, describing them as “new territory in terms of government shutdowns.” He added, “Our sole role is to keep this airspace as safe as possible. This is not about light travel locations, it’s about where the pressure is.”

Geoff Freeman, head of the US Travel Association, warned that the shutdown was “forcing difficult operational decisions that disrupt travel and damage confidence in the US air travel experience.”

Aviation expert John Nance told ABC the FAA was doing its best to prevent “any reduction in the margins of safety.” Still, he cautioned that “we’re facing the potential of almost a shutdown of the national airspace.”

Broader fallout

An AP analysis found that at least 39 air traffic control facilities reported staffing limits from Friday to Sunday, far above the pre-shutdown weekend average of 8.3. Over the past five weekends, the number has tripled to 26.2 facilities.

The shutdown’s impact is already spilling into other areas: investigators said it may delay the probe into Tuesday’s UPS cargo plane crash in Louisville that killed 12 people.

“At a minimum, the shutdown will certainly slow down the investigation,” said transportation attorney Matt Stoddard.

“The National Transportation Safety Board must interact with other parts of government, and those responses will certainly be slowed,” Stoddard stressed.

Long-term impact of shutdown on aviation sector

The government shutdown's impact is being closely watched by the industry. Despite currently manageable business conditions, carriers warn that flight bookings could drop sharply if the shutdown persists. More than 2,100 flights were delayed on Wednesday alone, and absenteeism among air traffic controllers has surged, with up to 40% failing to report to work at some of the nation’s busiest airports.

Duffy warned that if the government shutdown continues into the next week, the agency may be forced to close parts of the national airspace and impose time-based restrictions on space launches and general aviation flights.

The shutdown, which began on October 1, has already affected millions, shuttering services, delaying assistance programs, and putting over 750,000 federal employees on furlough. Lawmakers remain deadlocked over key provisions related to health insurance subsidies, with no resolution in sight.