Pat Shanahan, senior vice president of Airplane Programs for Boeing Commercial Airplanes, said Tuesday that the company has "a lot of flexibility" to accommodate increased production and future work at its Everett site without any extensive new buildings.

Shanahan said he woudn't rule out the option of minor add-ons to the sides of buildings for expansion. But he identified specifically two large areas now in use for temporary work that could be free in time to house extra production, including perhaps an assembly line to build the future 777X.

"We've got the surge line," said Shanahan, referring to the temporary 787 line in one bay.

"And the EMC will be free a lot sooner than most people think," Shanahan added, referring to the big aircraft repair shop Boeing acquired at the south end of Paine Field, now known as the Everett Modification Center.

(Above, Shanahan aboard the Korean Air 737 on display at the Air Show. Boeing photo.)

The surge line was set up to provide extra production capacity in case either the new South Carolina final assembly plant took a long time to ramp up or the introduction of the next model of the Dreamliner, the 787-9, disrupted production.

The surge line is currently being used to do re-work on Dreamliners but will switch to building production planes in the fall. Shanahan said Boeing has started hiring and training people to work on the surge line.

He said until the 787-9 comes on stream -- first deliveries are scheduled for early 2014 -- it's difficult to say exactly when the surge line can be stood down and the bay freed up for other work.

But Boeing has said the 787-9 is progressing well and Shanahan emphasized that at some point that bay will be free.

The EMC is being used now to do the modifications on all the Dreamliners built earlier and needing extensive re-work before delivery.

He said most work there will be completed next year, though some smaller portion of the work may drag out longer.

The freeing of space at the EMC depends upon Boeing beginning to clear the backlog of jets needing rework. That backlog has actually grown this year, with only six jets delivered to customers in the first half of the year while more than 18 rolled out of the factory.

Yet Shanahan insists that the logjam will soon dislodge.

He said the stream of deliveries will begin to match the number of jets rolling off the assembly line during the next three months. He said deliveries will rise above 3.5 jets per month during the quarter.

Boeing has recently touted the fact that Dreamliner No. 66 was the first jet to roll out straight to the field that required no major modification. However that jet is still undelivered weeks after it rolled out.

Shanahan said that's because it's backed up behind other planes delivered this year that will soon go to airlines.

"It's like standing in the grocery line," he said. "We haven't leap-frogged any of the airplanes ahead."

He said Boeing this month will finally deliver Dreamliner No. 7, which was the first production airplane after the six initial flight test planes. No. 7 entered final assembly in June 2009.

"So you have the tail end catching up with the front end," said Shanahan.

It certainly would be good news for the Dreamliner program if the 787 re-work backlog soon began to clear and is mostly gone by next year.

Shanahan's remarks make clear a big additional benefit: it could provide room for a dedicated 777X assembly line.

This still leaves open how Boeing will make the 777X wing.

If Boeing decides it should be made from carbon fiber composites, the wing likely couldn't be made in Everett without building a new facility.

Shanahan said Boeing hasn't backed away from its earlier assertions that a composite wing rather than aluminum is "the preferred design."

But he said the company is still working out the trade-offs between cost and performance and so it's too early to say what material it will be made from and whether a composite wing fabrication plant will be needed.