The Trump administration is facing pressure to protect the Federal Aviation Administration from further layoffs after hundreds of workers were fired over the weekend.
The job cuts were part of a government restructuring under Elon Musk, an adviser to President Trump who is heading a cost-cutting initiative.
Mr. Musk’s team has helped push through layoffs of thousands of workers across the government, including at the Transportation Department. But at the same time, the department’s secretary, Sean Duffy, has asked Mr. Musk, whose companies span the sectors of technology and transportation, to aid in addressing the agency’s aging air traffic control technology.
The firings come at a time when the F.A.A., the nation’s premier aviation safety agency, is dealing with several deadly plane crashes across the country, including a midair collision between an Army helicopter and American Airlines plane that killed 67 people on Jan. 27.
About 400 probationary workers — who were “hired less than a year ago” — were cut from the agency, according to Mr. Duffy, in a social media post on Monday responding to criticism from his Democratic predecessor, Pete Buttigieg.
“Zero air traffic controllers and critical safety personnel were let go,” Mr. Duffy wrote.
The Transportation Department added in a statement that the agency was continuing to hire and train air traffic controllers and aviation safety workers. However, union representatives say that some of the fired employees served in important support roles.