Bombardier's operations in Northern Ireland have been sold to the US company Spirit AeroSystems.
The Canadian company put the plants up for sale in May as part of a reorganization of the business.
The aircraft manufacturer employs about 3,600 people in Northern Ireland.
Spirit, based in Wichita, Kansas, is an important supplier to Airbus and Boeing. Earlier this year, Spirit's CEO said the company wanted to do more work for Airbus.
Buying Bombardier's Northern Ireland operation is part of the strategy.
The wings of the Airbus A220 are made at Bombardier Belfast's plant, and it also supplies other Airbus parts, especially engine covers.
Spirit also buys a Bombardier plant is Morocco and a repair facility in the United States.
Analysis: A strategic acquisition for Spirit
Bombardier workforce in Northern Ireland has been cutting for many years and insecurity.
At one point, the Canadian firm was on the brink of insolvency.
A new owner for the Belfast operations should bring some stability to the workforce and a long-term focus for the business.
This is a strategic acquisition for Spirit ̵
The unions are happy that the business has gone to a buyer rather than to a private equity fund.
Michael Ryan, Bombardier's chief of aerostructures, said employees would be updated on how the deal affects them over time.
He added: "W e are delighted that Spirit, a global manufacturer and supplier of high quality aerostructures, has recognized our unique offering and growth potential."
- How important is Bombardier to NI?
Unite union said: "It is a sale that provides hope for a positive future for Bombardier workers in Northern Ireland and their supply chain colleagues."
Bombardier, based in Montreal, has more than 68,000 employees in 28 countries.
It employs around 3600 people in several locations in Northern Ireland – east of Belfast, Newtownabbey, Dunmurry and Newtownards.
The Belfast plant builds wings for Airbus and is the largest high-tech manufacturer in Northern Ireland.