BOEING factory workers voted against the company’s latest contract offer and remain on the picket lines six weeks into a strike that has stopped production of the aerospace giant’s bestselling jetliners.

Local union leaders in Seattle said that 64 per cent of members of the International Association of Machinists and Aerospace Workers who cast ballots on Wednesday voted against accepting the contract offer.

“After 10 years of sacrifices, we still have ground to make up, and we’re hopeful to do so by resuming negotiations promptly,” Jon Holden, the head of the IAM District 751 union, said in a statement on Wednesday evening. 

“This is workplace democracy — and also clear evidence that there are consequences when a company mistreats its workers year after year.”

A spokesperson for Boeing said officials didn’t have a comment on the vote.

The dispute, which began on September 13, comes during an already challenging year for Boeing, which became the focus of multiple federal investigations after a door panel blew off a 737 Max plane during an Alaska Airlines flight in January.

The strike has deprived the company of much-needed cash that it gets from delivering new planes to airlines. On Wednesday, the company reported a third-quarter loss of more than $6 billion (£4.6bn).

Union machinists assemble the 737 Max, Boeing’s best-selling airliner, along with the 777 and the 767 cargo plane at factories in Renton and Everett, Washington.

The latest rejected offer included pay raises of 35 per cent over four years. The version that union members rejected when they voted to strike last month featured a 25 per cent increase over four years.

The union, which initially demanded 40 per cent pay boosts over three years, said the annual raises in the revised offer would total 39.8 per cent, when compounded.

Boeing has said that average annual pay for machinists is currently $75,608 (£58,000).

Boeing workers told Associated Press reporters that a sticking point was the company’s refusal to restore a traditional pension plan that was frozen a decade ago.

“The pension should have been the top priority. We all said that was our top priority, along with wages,” Larry Best, a customer-quality co-ordinator with 38 years’ experience at Boeing, said on a picket line outside a Boeing factory in Everett, Washington.

Mr Best said: “Now is the prime opportunity in a prime time to get our pension back, and we all need to stay out and dig our heels in.”