The more than 900 British Airways staff working in south Wales are at risk of losing their jobs as the airline proposes to cut 399 jobs.
BA says the industry faces "the deepest structural change in its history."
Airlines have reported a collapse in the number of passengers since the beginning of the coronavirus pandemic.
British Airways say at this point, the job losses are "proposals" and they are entering a consultation period with workers at their Welsh sites in Llantrisant, Blackwood and Cardiff Airport.
British Airways does not operate commercial flight from Cardiff but there is a maintenance centre at the Welsh Government owned airport.
British Airways, Ryanair and Virgin Atlantic have all announced plans to make thousands of staff redundant.
IAG, which owns British Airways, has said it does not expect demand for air travel to recover before 2023.
Andrew RT Davies, Welsh Conservative MS for South Wales Central, has described the announcement as "devastating news" for employees at the three south Wales sites.
A spokesperson for the Welsh Government said: “This will be very worrying news for BA workers and their families".
“We recognise the impact Covid-19 is having on the aerospace sector and the wider pressures on the industry. The Economy Minister has previously written to the UK Government to press for further, targeted assistance for the sector and we will continue to make the case.
“The Welsh Government stands ready to all it can to support people affected, including through the Welsh Government’s ReAct programme and our wider employability and skills offer, if BA’s consultation results in job losses across South Wales.”