The futures of 2,500 Spirit remain uncertain despite today's announcement Airbus will take over the A220 wing manufacturing and assembly facility in Belfast.
About 800 of the 2,500 workers at the plant assemble the wings - and Boeing has indicated it is not interested in the rest of the Belfast site.
Alan Perry, GMB Senior Organiser, said:
"The best solution for the Belfast sites is to remain as one identity.
"Today's announcement raises serious concerns over the future of more than 2,50O workers who don’t work on the Airbus Contract.
"GMB has engaged with Stormont ministers who agree a carve up does not benefit the company or the wider Northern Ireland economy.
"We will now take our campaign to Westminster on Wednesday [30 March] to meet with officials from the dept of business and trade.
"This company which has been here for more than 150 years we will fight tooth and nail to protect and maintain jobs for future generations."
