In 2009, Boeing decided to build the massive final assembly building in North Charleston because the original 787 factory in Everett, Wash. didn’t have enough capacity to keep pace with the record demand for the new jet.

Now, there’s a creeping possibility that, when the time comes, the younger sibling site will be the only place Boeing assembles its largest Dreamliner model.

The long-held suspicion, based on the logistics of Boeing’s 787 supply chain, seemed to take another step closer to truth this week at the Paris Air Show.

According to The Seattle Times, Boeing’s commercial airplanes chief Ray Conner was “surprisingly noncommittal” Sunday when asked whether the longer fuselage sections of the proposed double-stretch 787-10 will be flown from North Charleston to Everett, like those for the 787-8 and -9 are now.

“We’re still looking at that,” Conner was reported as telling told a group of journalists on the eve of the biggest aerospace event of the year. “We haven’t made the determination on that yet.”

Washington officials have “worried for some time” that the logistical issues unique to the 787-10 could mean it will be built exclusively in South Carolina, according to The Seattle Times article.

Bolstering that argument, the officials noted the final assembly building in North Charleston is big enough to fit four of the 787-10s nose-to-tail, whereas the Everett plant might not be.

“Conner’s noncommittal answer seemed odd when the formal launch of the jet is imminent,” the Seattle Times wrote, referring to the expected launch of the third Dreamliner model this week. “It may be that Boeing is reserving judgment until South Carolina ramps up on building the current 787-8 model and proves it can do that work.”

The North Charleston final assembly line is now making roughly two 787-8 airplanes per month, as part of an overall program rate of seven per month, and is scheduled to build three per month by the end of the year, as part of an overall expected program rate of 10 per month.

The aft- and mid-body factories at the airport-adjacent complex make their fuselage components for every 787, including, as of this year, for the stretch 787-9.

While the company has not confirmed all the details of the 787-10, which will seat between 300 and 350 passengers when it enters service by the end of the decade, the North Charleston component factories will also make its fuselage sections.

Like the 787-9 stretch, the 787-10 stretch will involve adding another round piece of fuselage to the 787-8 base model. The key question is how, because if the “donut” is appended to the mid-body, it might make it too long to fit in the Dreamlifters, the modified 747s that transport 787 parts from around the world for final assembly in Everett and North Charleston.

“We’re weighing a number of different options,” Conner said, according to The Seattle Times article. “You could do the donut in the mid. You could do the donut in the aft.”

Boeing South Carolina spokeswoman Candy Eslinger did not respond to a request for comment on the 787-10 speculation.

Boeing has clearly signaled its confidence in the South Carolina operation this year, headlined by an April pledge to invest $1.1 billion and hire 2,000 more people here in exchange for a government incentive package that includes $120 million and various tax breaks.

Specifically, the company is setting up an information technology and engineering centers here and last month issued a request for proposals for another factory in the area to house design and manufacturing of the coverings for the forthcoming 737 MAX’s engines.

Saj Ahmad, a London-based analyst with, has been predicted for months that the 787-10 will be assembled exclusively in North Charleston.

On Monday, he said official word from the company is “inevitable” and constitutes “further evidence that the Low Country has more opportunity to snare Boeing work ahead of WA,” or Washington state.

“This is Boeing’s way of putting it out in the open — so as not to risk ire of the WA-based unions,” Ahmad said in an email, referring to Conner’s intriguingly open-ended remarks this week. “To me, it’s more a question of ‘when’ they formally announce it, not if.”