WASHINGTON, Feb 17 (Reuters) - The Federal Aviation

Administration fired fewer than 400 employees out of its

workforce of 45,000, Transportation Secretary Sean Duffy said on

Monday, as questions rise around air traffic safety amid a spate

of recent plane accidents.

Duffy posted the number of layoffs in a social media post

message on X, formerly known as Twitter, responding to a post by

his Democratic predecessor Pete Buttigieg, who has been critical

of the Trump administration's Department of Transportation.

"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 wrote on Monday.

The Trump administration sent air traffic controllers buyout

offers but later said they were not eligible, also declaring

other safety officials, including TSA officers, ineligible. The

FAA remains about 3,500 controllers short of targeted staffing

levels.

The Professional Aviation Safety Specialists union said

Saturday the FAA had fired several hundred probationary FAA

employees.

The union said Monday it believed just under 300 FAA workers

it represents were fired, including maintenance mechanics,

aeronautical information specialists, aviation safety assistants

and management and program assistants.

"These are positions that are vital to supporting public

safety," a union spokeswoman said.

The FAA and Transportation Department have declined to say

what jobs the fired workers held or why they were fired.

The disclosure came on the same day that Elon Musk's

government downsizing team DOGE was visiting the FAA's Air

Traffic Control command center in Warrenton, Virginia, Duffy

said.

Senator Maria Cantwell, the top Democrat on the Senate

Commerce Committee, on Monday slammed the Trump administration

for firing FAA employees who inspect and maintain air traffic

control communications, radio and computer systems - especially

after a series of fatal crashes.

"The FAA is already short 800 technicians and these firings

inject unnecessary risk into the airspace - in the aftermath of

four deadly crashes in the last month," she said.

USDOT said Monday FAA "continues to hire and onboard air

traffic controllers and safety professionals, including

mechanics and others who support them."

Duffy said on X that the Trump administration plans to

overhaul what he called "our outdated, World War II-era air

traffic control system."