The Unite union has said it will campaign for Bombardier's Northern Ireland operation to be nationalised if a new owner seeks to break up the company.
Announcing the sale of its aerostructures and engineering operations in Belfast, Newtownabbey, Dunmurry and Newtownards on Thursday, the Canadian giant said it was committed to finding a buyer that will "operate responsibly" in Northern Ireland.
A number of major companies involved in aerospace components have already been suggested as potential buyers, but the prospect of a venture capital-led takeover has prompted fears among unions.
Susan Fitzgerald from Unite said such an outcome could spell the "kiss of death" for Bombardier's 3,600 workforce and could threaten thousands more jobs in the supply chain.
"The idea of somebody coming in and picking what they want and scrapping the rest is just a recipe for job losses, not just within the Bombardier workforce, but in the supply chain as well," she said.
"Shorts was nationalised in the past. If that's what it takes to secure jobs in communities, we don't have a problem putting that out there and standing over it. If we thought the workforce could be broken up, we would put forward that as a campaigning demand and we would be vigorous in pursuing it.
"We have no choice. Do we just sit by and let market forces dictate what happens to communities, to jobs and people's lives? The answer from Unite is no."
While Bombardier has previously expressed concern over the uncertainty posed by the threat of a no-deal Brexit, the company said on Thursday that its exit from Northern Ireland was down to a strategic move away from commercial aviation.
But the UK's eventual status within the EU is likely to be a significant factor in who buys the business.
American-owned manufacturer Spirit AeroSystems and UK-based GKN have emerged as potential front-runners.
Both companies declined to comment yesterday on a potential bid for Bombardier.
GKN was recently acquired by Melrose Industries in a hostile £8bn takeover and may not be geared toward an acquisition.
Spirit Aero, which is heavily dependent on Boeing's crisis-hit 737 Max, has recently expressed interest in acquisitions to diversify its business.
Airbus, which is one of the biggest customers for Bombardier's Northern Ireland operation, could also potentially step in. The European aerospace giant owns the majority stake in the A220 aircraft series, which Bombardier makes the wings for. The sale of the business is likely to include the wing programme.
In a statement, Airbus said it does not anticipate any impact on A220 production as a result of the sale, but added: "We will of course monitor the evolution with our partner, Bombardier, to ensure that this is the case."
China's state-owned AVIC, which acquired NI aircraft seat manufacturer Thompson Aero three years ago, could also see Bombardier as an opportunity to strengthen its stake in the UK.