The future of Shorts in Belfast and its 5,500 employees is threatened after parent company Bombardier Aerospace laid off another 560 workers.
The company blamed ongoing financial difficulties experienced by major American airlines for the decision.
Another 330 jobs at the plant in unionist east Belfast could go if Delta airlines - one of Bombardier’s major US customers - fails to take up a significant order it has placed.
“Today’s announcement is due to market forces outside of the company’s control following Bombardier’s lengthy consultations with airline customers, some of whom face severe financial challenges,” a company spokesman said.
The SDLP’s Sean Farren called on the British government to support Bombardier with financial help.
He said suppoer for a new contract was “absolutely vital to ensure that Bombardier can build the planes in Belfast. Such a prize would provide security of employment for a long period. It is crucial that this opportunity must not be lost,” he said.
* Direct flights between Belfast and New York are to begin next May, it was confirmed yesterday. The new service by Continental Air-lines will see daily flights between Belfast International and New York/ Newark from May 27.
Flights will take just seven and a half hours - cutting several hours off the journey.