Construction on the 1.3 million-square-foot (121,000-square-meter) building continues, as it will for the next 18 months, with the roll-in of new tools and equipment. Preproduction parts for the 777X are underway. Nearly 130 mechanics are testing equipment and the first prototype parts, while another 170 employees have moved into the offices so far.

"It's pretty incredible," said Brett Miller, a 777X tool engineer, noting that real tools and equipment that previously existed only on computer screens and design reviews are coming together.

The building will support fabrication of the 777X wing, the longest wing Boeing has ever built, and turn the Everett site into a center for advanced carbon-fiber technology.

Production of the first 777X is expected to begin next year. Following flight testing and certification programs, the first delivery is scheduled for 2020. The aircraft's GE9X turbofan engines also recently passed two testing milestones in preparation for their delivery to Boeing.

The company has invested more than $1 billion to construct the new facility. In grand opening ceremonies for the building in May, Boeing and community leaders said the company's sizable capital investments in the 777X, along with other Boeing programs and capabilities based in the region, will provide continued jobs and benefits to employees and their communities for years to come.