The Trump administration has begun firing hundreds of Federal Aviation Administration (FAA) employees, according to the Professional Aviation Safety Specialists (PASS) union, weeks after a fatal mid-air plane collision in Washington DC.

Several hundreds of the agency's probationary workers - who have generally been in their positions for less than a year - received the news via email late on Friday night, a statement from PASS's head, Alex Spero said.

It is part of a cost-cutting drive, driven by Elon Musk's Department of Government Efficiency (Doge), which aims to drastically cut the federal workforce.

Spero called the firings "shameful" and said they "will increase the workload and place new responsibilities on a workforce that is already stretched thin".

The BBC has contacted the FAA and Department of Transport for comment.

According to Spero's statement, workers impacted include systems specialists, safety inspectors, maintenance mechanics and administrative staff, among others.

Criticising the move, Spero said the FAA is "already challenged by understaffing", and that the decision to cut staff was "unconscionable in the aftermath of three deadly aircraft accidents in the past month", including the deadly crash in Washington DC's Ronald Reagan airport, in which 67 people were killed.

Jason King, who is among those laid off, said he was worried about how the move would impact aviation safety.

He told WUSA9, an affiliate of the BBC's US partner CBS, that firing people directly involved with air safety is "concerning for public safety in our national airspace."

Mr King, whose work at the FAA involved directly addressing safety concerns, said the cuts "threaten public trust and increases the likelihood of future accidents."

"Aviation safety should never be treated as a budget item that can just be completely cut," he added.

On Monday, a team from Elon Musk's SpaceX was set to visit the FAA to suggest improvements to the US's air traffic control system, following the Washington DC plane collision in January.

Though the National Transport Safety Board has not yet determined the cause of the collision, staffing levels in air traffic control at the airport, were reportedly below normal levels on the evening of the crash.

Transport Secretary Sean Duffy said the SpaceX team's visit to the FAA would give them a "first-hand look at the current system", and would allow them to figure out how they make "a new, world-class air traffic control system that will be the envy of the world."

He added that he plans to visit the FAA Academy - which provides training for the organisation's workforce - later this week, to learn more about staff member's education "and how we can ensure that only the very best guide our aircraft".

President Donald Trump caused controversy last month when he suggested diversity programmes supported by his predecessors had lowered hiring standards that could have affected the Washington DC plane crash.

The Trump administration has ordered government agencies to fire nearly all of their probationary employees, who have not yet earned job protection. It is a move that could potentially affect hundreds of thousands of people.

Among those losing their jobs in Friday's cuts were half of the Centers of Disease Control's so-called "disease detectives", multiple health officials told CBS.

The researchers - officially officers serving in a two-year programme in the organisation's Epidemic Intelligence Service - are often deployed on the front lines of major disease outbreaks.

Many members of the scheme have gone on to rise in the agency's ranks.

President Trump has also asked the Supreme Court to allow him to fire the head of an independent ethics agency that protects whistleblower federal employees.

Hampton Dellinger, the head of the US Office of Special Counsel, sued the Trump administration after being fired last month.

It is thought to be the first case related to Trump's series of executive actions to reach the country's highest court.

Since taking office, the president has cut more than a dozen inspectors general at various federal agencies.