Bombardier's CS100 passenger jet, which is part-built in Belfast, has been awarded certification by Canada's transport authority.
That means the aircraft could be in the air as early as the middle of next year.
The firm's Belfast factory has been producing the wings for both of its CSeries jets.
Last month, the Belfast Telegraph revealed that the workforce here had made between 15 and 20 fuselage mid-sections for the aircraft after work was transferred from the company's manufacturing partner in China to Northern Ireland.
Welcoming the green light for the CS100, Michael Ryan, vice-president and general manager of Bombardier Belfast, said: "Given our involvement in the CSeries aircraft programme, in particular in the design and manufacture of the advanced composite wings, this is an achievement of which all our employees and our supply chain should be justly proud."
"The wings are produced using a patented resin transfer infusion process developed by our Belfast engineers, and represent a step change in aircraft wing design and manufacture."
The Canadian firm's certification - which passes the aircraft fit in all aspects of airworthiness - has been speculated on in recent weeks.
Bombardier's Fred Cromer, president of commercial aircraft, said the sign-off was "a historic moment". "Years of effort and collaboration culminate in a very proud moment for many as we celebrate the CS100's Transport Canada certification," he added.
Also welcoming the sign-off, Enterprise Minister Jonathan Bell said: "Certification of the CS100 represents the successful completion of years of design, development and testing of this all-new aircraft, the advanced composite wings for which are designed and manufactured in Northern Ireland.
"I congratulate the whole team at Bombardier, and especially Michael Ryan and his staff."
Belfast's role in the CSeries has increased significantly, from initially being tasked to work only on the wing sections of the jet.
But Bombardier has been struggling with securing sales for the long-delayed jet.
While the narrow-bodied aircraft has received 243 orders so far, that is lower than the company's initial target of 300.
The firm recently warned it faced a "serious financial crisis" and planned to reduce its operating costs in Belfast by a fifth over two years.