EVERETT, Wash. — Riveters once ruled here, as Boeing airplanes rolled off the line and into the sky from giant factories where rivers of aluminum were pounded into form and function. And Boeing, founded in nearby Seattle in 1916 in the era of the Sopwith Camel, returned the favor, building up the Puget Sound region as a blue-collar powerhouse from the 1940s through the commercial jet age. Almost half of the company’s 171,000 employees still call Washington State home.

But the next chapter of that old relationship has become a cliffhanger of politics, economics and perhaps, some suspect, brinkmanship and bluff. Where the company will assemble its next generation of commercial airplane, the 777X — which only a few months ago looked locked-down certain to be right here — is now up for grabs, with a national scramble of states and cities bidding for Boeing’s hand with tax breaks, incentives and promises of labor congeniality.

With a deadline looming this week for best offers, and a decision promised by the company early next year, tens of thousands of jobs and billions of dollars in wages and taxes are at stake, along with the identity of a region that long ago claimed the jet age as its symbol, in Seattle’s revolving Space Needle.

“It would be the death spiral of aerospace in Washington State,” said Ray Stephanson, Everett’s mayor, contemplating the possibility of Boeing’s building the 777X in some other state. As he spoke in his office, a scale model 777-300, angled as though in takeoff, sat by a window. “There’s a tremendous amount of anxiety.”