Big rumblings are going on at America's airplane capital -- the Boeing Co. aircraft factory north of Seattle.
Engineers are moving forward with building the world's biggest twin-engine jetliner.
They're calling it the 777-9X, the first aircraft of the 777X family.
For air travelers and aviation enthusiasts, there's a lot to be excited about.
For one thing, there's the wing: It's big.
It's so big, in fact, they had to fold it.
Specifically, the 777-9X will have hinges on its wingtips. The hinges will fold up, allowing the plane to shorten its wingspan when it's rolling across airport taxiways.
It will be the first design of its kind on any commercial airliner, Boeing says.The plane will have the widest wingspan of any aircraft in the company's 99-year history: 235 feet, 5 inches (71.8 meters).
To put it another way: It's wider than four 53-foot (16-meter) semi-truck trailers parked end to end.
The hinged wingtips alone will measure 12 feet. Locking pins will prevent them from folding during flight, Boeing tells CNN.
Prototype testing is expected to get underway soon, Boeing says.
During testing, engineers plan to fine-tune and try to perfect the final design.
These giant wings will give the airliner extra lift, like a giant sailplane glider.
They'll help the plane save an overall 12% more fuel than the Airbus A350, Boeing says.
Initial versions of the 777 have been flying since the mid-1990s, and the 777X has been in the pipeline for two years already.
But the buzz got louder last week when Boeing announced it finalized a basic design.
Digital cheers popped up all over Twitter and Facebook.
"The inside is amazing," Rohan Gosh tweeted.
Twitter user Andres Vallekas expressed his delight with three hearts.
