More than 300 Menzies Aviation workers at Glasgow and Edinburgh airports are facing redundancy.
The company, which provides baggage handling among other services, said it has begun the 45-day redundancy consultation period with 318 staff.
Menzies Aviation said the decision was taken with “great sadness” but said it had “no choice” as air travel is not forecast to return to pre-coronavirus levels in the near future.
A representative for the Unite union said workers are “frustrated and angry”, adding “these job losses do not need to happen”.
Unite said Menzies Aviation employs about 300 workers at each airport, and about half of these staff face redundancy – 160 in Glasgow and about 150 in Edinburgh.
Pat McIlvogue, Unite regional industrial officer for Glasgow Airport, said: “Unite has been informed that more than half of Menzies Aviation’s workforce based in Glasgow airport are at risk of imminent redundancy.
“We are deeply frustrated and angry that despite the company calling for the job retention scheme to be extended so that job losses could be avoided they have still forged ahead with this announcement.
“Unite fully understands the situation facing the civil aviation industry, which is why we have been calling for a co-ordinated national response so that we can safeguard thousands of Scottish jobs.
“However, let us be clear, these job losses do not need to happen and this is a deliberate choice by Menzies Aviation to slash its workforce.”
Giles Wilson, Menzies chief executive officer, said: “It is with great sadness we have taken the difficult decision to enter into consultation with our employees and unions to reduce the size of our airport teams in the UK and Ireland.
“This has been the most challenging period the UK aviation sector has ever seen and whilst a small number of flights have started operating again, we do not expect volumes to return to pre-Covid 19 levels in the near future.
“We’re left with no choice therefore but to take action to match our workforce to the volumes we anticipate through the winter and well into 2021, to ensure Menzies is sustainable now and fit for the future.
“We recognise the significant impact this will have on our colleagues who will be leaving us and throughout this process we’ll do everything we can to minimise the number of job losses across the network.”