Boeing has brought together the major fuselage sections to form the first 777X plane.

The new plane is expected to take to the skies for the first time in 2019.

In a major production milestone called ‘final body join,’ Boeing teams connected the plane’s nose, mid and aft sections in the company’s factory in Everett, Washington.

The jet now measures 252 feet long (77 meters) from nose to tail, making it the longest passenger jet the manufacturer has ever produced.

“The 777X is a new plane and a new production system,” said Josh Binder, vice president and general manager of the 777X.

“With the 777X, the production system was integrated into the development program sooner than any other plane, and the team is doing a great job of hitting our milestones as expected.”

The 777X builds on the market-leading 777 and the 787 Dreamliner to offer airlines the largest and most-efficient twin-engine jet in the world.

The plane provides 12 per cent lower fuel consumption and ten percent lower operating costs than competing planes.

The first 777X introduced will be the 777-9 model, which can seat 400 to 425 passengers in a standard configuration and offer a range of 7,600 nautical miles.

The first 777X test plane for static ground testing was completed in September 2018.

First delivery is slated for 2020.