Unite is appealing to people to get behind its campaign to keep jobs and incomes in the community.
The warning comes after aerospace parts firm SPS Technologies announced more than 350 job losses across the East Midlands, while Turbine Surface Technologies Ltd has announced more than 100 job losses.
Meanwhile, Nottinghamshire employer Rolls Royce is planning to shed 3,000 jobs across the UK.
With a huge decline in new orders and maintenance work – a knock-on effect from the pandemic hit to the aviation sector – many more jobs are at risk in the industry right across the region.
The East Midlands is heavily reliant on the aerospace sector, with 25,900 workers being employed.
Unite regional secretary for the East Midlands, Paresh Patel, said: “Aerospace is absolutely crucial to our economy but the lack of action at Westminster means we now stand at five to midnight and could be looking at a very bleak future.
“Jobs are going by the day and our world-leading status is slipping away.
“Without the support this sector is crying out for we will lose thousands of jobs. It is a travesty and we are pleading with the government to waste no more time.”
Unite is urging everyone who is employed in the industry to contact their MP and ask them to lobby the government.