Bombardier says a new airplane order worth more than £2 billion will keep workers in jobs.
Delta Airlines has ordered 40 of the CRJ900 NextGen jets but could request a further 30 of the aircraft in the future.
Workers at the Canadian aerospace company's Belfast plant are responsible for the design and manufacture of the centre fuselage, engine nacelles and composite wing components.
A spokeswoman said: "We in Belfast will once again benefit, given the significant role we play in the CRJ900 NextGen programme.
"This order is a further vote of confidence by customers in Bombardier's products, and in the skills and capabilities of our workforce here in Belfast."
Last week Vistajet, a private jet charter firm, signed a deal for up to 142 global Bombardier-built business jets in a deal worth more than £4.8 billion - the largest in the company's history.
The spokeswoman said: "Orders such as these over the past week are helping to maintain our current manpower levels and secure the long-term future of our design and manufacturing operations in Northern Ireland."