Nearly two-thirds of workers reject offer that includes a 35 percent pay rise.

Boeing workers on the West Coast of the United States have voted to reject the aircraft giant’s latest contract offer and extend their nearly six-week strike.

Nearly two-thirds of workers rejected the offer, which included a 35 percent wage rise over four years but did not restore a defined pension plan sought by many employees, the Seattle branch of the International Association of Machinists and Aerospace Workers union said on X.

IAM District 751 President Jon Holden said the union had made “tremendous gains” in negotiations but had not gone far enough to meet members’ demands.

“Senior members with decades of experience, new members with a few months, and members from different backgrounds all stood together to support each other. I’m proud of you and your strength,” Holden said in a statement.

“This membership will continue to stand on the line, picketing for the contract they deserve. There is much more to do, and we will work to get back to the bargaining table. Our members’ voices will be heard.”

About 33,000 workers have been on strike since mid-September when union members overwhelmingly rejected Boeing’s proposal for a new four-year contract.

The industrial action has brought operations to a halt at two Boeing factories in the Seattle area that produce the 737 Max and 777, depriving the company of much-needed cash from its aviation business.

The union vote is another blow to Boeing after a difficult year that has thrust longstanding concerns about safety and quality standards at the aircraft maker into view.

The company has been under investigation by multiple agencies since an incident in January in which a 737 Max plane operated by Alaska Airlines lost a door panel while in mid-flight.

On Wednesday, the company reported a third-quarter loss of more than $6bn.

Boeing stock dropped 1.76 percent after the latest results, adding to a slump that has seen its share price fall nearly 38 percent so far this year.