Luton Airport is looking to cut 250 jobs as it prepares to see passenger numbers fall by 70% this year due to the pandemic.
Bosses say they do not expect the aviation industry to recover and return to the kind of business it saw in 2019 until 2023 or 2024.
The airport - which is owned by Luton Council - announced it had launched a consultation having placed 250 roles at risk of redundancy.
"This is an extremely challenging period, made all the more difficult given the value we place in our airport family who have had a role to play in the airport's success," said Chief Executive Alberto Martin.
"During the consultation we will be working to support our colleagues as much as possible and will be seeking ways to avoid redundancies where possible - such as exploring opportunities for employment elsewhere in the business."
Unite the Unite said the job cuts would affect nearly a third of workers directly employed by the airport itself.
But it expects many others whose jobs rely indirectly on the airport to face uncertainty too. More than 27,000 jobs are sustained by the Bedfordshire base through contractors and supply chains.
Unite regional officer Jeff Hodge warned the consultation was premature.
"With the government looking at air bridges and the job retention scheme (JRS) continuing until October, this decision is simply premature. Any decision on job losses can and should be delayed until a clearer picture is available.
“But we are also calling on the government to play its part. Job losses in the aviation sector are growing directly as a result of the government’s failure to provide a sector-specific support package for the industry.
"The government first promised support way back in March, so why are the industry and workers still waiting?
“Aviation will return to good health but it will take time, which is why JRS should be extended and specific support should be provided to preserve the employment of airport and airline staff.
“The reality is that without urgent and decisive action from the government, more aviation jobs will go.”
Passenger numbers are expected to remain well below pre-pandemic levels for many months to come - despite the prospect of "air bridges" being agreed to allow quarantine-free travel between the UK and certain countries.
Luton Airport said it would be consulting with Unite the Union as well as individual staff members.
The impact of coronavirus on Luton Airport has also had a major impact on the finances of the borough council - which relies on dividends to fund millions of pounds worth of services.
The local authority has also announced more than 400 jobs losses - affecting 14% of its workforce - and warned key services faced significant cuts.
It is predicting a £50m shortfall in its budget because of the pandemic. It had been relying on an income of £33.5m from Luton Airport to fund near a quarter of its services in 2020/21.