The CAA has announced it will look to outsource the Aeromedical Centre (AeMC) that provides medical services to pilots and also expert advice to airlines.
Responses to the CAA's consultation held last year show the overwhelming views of stakeholders, including airlines, unions, pilots and aeronautical medical examiners, were against the move.
The unions accuse the CAA of going through the motions in its consultation exercise and reiterated the view of staff that all medical services should remain within the CAA.
They also stated they are uncomfortable that the CAA programme board did not have the medical expertise on it to safeguard safety and fear that outsourcing the AeMC could result in safety being compromised for passengers and staff working in the aviation industry.
Jeremy Gautrey, PCS national officer for aviation, said: “The decision to disregard the majority views of stakeholders, including one of the UK's biggest airlines, is clearly a commercial decision and not one founded on safety.
“The medical services provided by the CAA are recognised as market leaders across Europe and the breakup of the medical department and possible outsourcing could result in safety decisions being outweighed by commercial interests.”
Steve Jary, Prospect national officer for aviation, said: "The CAA is increasingly putting cost before safety.
“Outsourcing essential medical services will result in a poorer service to pilots, airlines and the travelling public. The CAA executive board needs to listen and put safety, not commercial interests at the heart of its decision making."