US Transportation Secretary Sean Duffy has warned that air travel capacity will be cut by up to 10% at 40 major airports over the coming days, if the government shutdown continues.
The decision, which is expected to affect domestic flights only, was made because air traffic controllers had been reporting fatigue, the head of the Federal Aviation Administration (FAA) said at a briefing alongside Duffy.
Some 1.4 million federal workers, from air traffic controllers to park wardens, are working without pay - or are on forced leave - because the US Congress has not agreed on a federal funding budget.
Unions say many employees are becoming ill with stress or are being forced into taking second jobs.
On Wednesday, the impasse became the longest shutdown in US history.
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.
The names of the affected airports - all high-traffic locations including Atlanta, Dallas/Fort Worth, Denver, Chicago O'Hare, and Los Angeles - will be released soon. Cancellations could affect between 3,500 and 4,000 flights per day.
Duffy stated the action is necessary to ensure safety and efficiency in air travel. If the shutdown continues, further restrictions may be implemented.
Airlines like American Airlines and Southwest Airlines are closely monitoring the situation and preparing to inform customers about potential impacts on their travel.
With workers facing immense pressure, many air traffic controllers are voicing concerns over their ability to maintain the high safety standards expected in aviation.
