More details have emerged about staff cuts hitting the Federal Aviation Administration, while the USA’s top transportation official defends the layoffs as part of an FAA overhaul he insists will not impinge safety.

The Professional Aviation Safety Specialists, a union representing some FAA workers, late last week revealed that some workers had been cut, but the group then provided few details.

It now says 133 of its members were let go in recent days. Those workers include FAA aeronautical information specialists, who evaluate and prepare navigation maps, routes, charts procedures and flight paths, and maintenance mechanics, who maintain air traffic control facilities.

Other eliminated FAA workers included aviation safety assistants, who maintain office records, supplies and data reports, and environmental protection specialists, who evaluate environmental impacts, ensure compliance with environmental requirements and otherwise perform “administrative or programme work related to environmental protection programmes”.

The staff cut come as part of a broader government overhaul by President Donald Trump.

The FAA has revealed little information about the layoffs other than to say it continues hiring air traffic controllers and other safety staff. The agency has not responded to a request for more information.

However, Sean Duffy, secretary of the US Department of Transportation, the FAA’s parent agency, defended the layoffs in a 17 February post on X.

“The FAA alone has a staggering 45,000 employees. Less than 400 were let go, and they were all probationary, meaning they had been hired less than a year ago. Zero air traffic controllers and critical safety personnel were let go,” Duffy writes. “I will not rest until I return the Department of Transportation and its incredible employees to its mission of efficiency and safety.”

Duffy’s message responded to an earlier posting by former DOT secretary Pete Buttigieg, who wrote, “The flying public needs answers. How many FAA personnel were just fired? What positions? And why?”

The FAA has for several years been seeking to ramp air traffic controller hiring amid a shortage of those critical safety workers. The agency has said many of its air traffic control facilities are badly understaffed.

Story updated on 18 February after PASS revised to 133 the number of FAA employees it says were cut. The union had previously said nearly 300 workers were laid off.