Huge tariffs placed on Bombardier in the United States could result in 4,000 jobs being lost in the North.
Antrim and Newtownabbey council last night voted unanimously to support the Bombardier jobs campaign.
Union officials gathered to lobby the local representatives.
"This is an issue not just for 4,000 workers and their families," said Susan Fitzgerald from Unite.
"It affects the broader supply chain which we estimate is upwards of 20,000 workers.
"It's an issue for the Northern Ireland economy."