Transportation Secretary Sean Duffy warned there will be a 10% reduction in air travel capacity at 40 major airports in the US starting Friday morning, if the government shutdown continues.

The decision was made because air traffic controllers have been reporting issues with fatigue, the head of the Federal Aviation Administration (FAA) said at a briefing with Duffy on Wednesday.

It is unusual, just as the shutdown is unusual, just as the fact that our controllers haven't been paid for a month is unusual, said FAA chief Bryan Bedford.

During the shutdown, now the longest in US history, controllers have had to keep working without pay, prompting some to call out sick or take side jobs.

The flight reductions will be gradual, starting at 4% of domestic flights on Friday, then rising to 5% on Saturday and 6% on Sunday, before hitting the full 10% next week, Reuters reported after the announcement, citing four unnamed sources.

The names of the affected airports - all high-traffic locations - will be released on Thursday, the officials said. The cancellations could affect between 3,500 and 4,000 flights per day.

Duffy stated, We are seeing pressures build in a way that we don't feel - if we allow it to go unchecked - will allow us to continue to tell the public that we operate the safest airline system in the world. He emphasized that despite the challenges, air travel is still considered safe, and the decision to cancel flights is made to maintain safety and efficiency.

A spokesperson for Southwest Airlines mentioned that they are still evaluating how the flight restrictions will affect their services, urging Congress to resolve the impasse swiftly. Delta Airlines declined to comment. With the shutdown starting on October 1, most federal workers were sent home without pay, but essential staff, including air traffic controllers, have continued to work without compensation.

As the impact of the shutdown intensified, the aviation sector began experiencing delays and cancellations, emphasizing the critical nature of resolving the funding issues as soon as possible. Air traffic controllers are texting 'I don't even have enough money to put gas in my car to come to work,' highlighted Nick Daniels, president of the labor union representing aviation workers.