Boeing logo is seen in this illustration taken July 26, 2025. REUTERS/Dado Ruvic/Illustration

By Dan Catchpole

(Reuters) -Boeing is expanding plans to replace striking St. Louis-area workers who assemble fighter jets and munitions with new hires through year's end, management announced on Thursday in an internal memo shared with Reuters.

Roughly 3,200 members of the International Association of Machinists and Aerospace Workers (IAM) District 837 have been on strike since August 4.

The first group of replacement workers for munitions production and assembly mechanics will begin training on Friday, according to the memo from Boeing Vice President Dan Gillian.

Boeing is also evaluating moving some work to third parties, Gillian said.

Boeing declined to comment on the memo or say how many replacement workers would start training.

Union officials and members said the move was largely a bluff, noting their jobs require weeks to several months of training, and getting a security clearance needed for many of the defense jobs can take up to six months.

U.S. Senator Bernie Sanders urged Boeing in a letter sent on Wednesday to end the eight-week-long strike.

"Do the right thing," Sanders said in his letter to Boeing CEO Kelly Ortberg. "Sign a fair contract."

Boeing management has said the company will not significantly increase its offer, which workers rejected.

Sanders, an independent from Vermont who often votes with Democrats, along with Democratic Senator Ed Markey of Massachusetts and Republican Senator Josh Hawley of Missouri, used a Senate committee hearing on Wednesday to slam Boeing's stance in labor talks.

The committee was reviewing President Donald Trump's nominations to key labor positions, including Boeing's chief labor counsel Scott Mayer to the National Labor Relations Board.

"The concept of fairness is an elusive one," Mayer said when asked by Hawley what would be a fair resolution to the strike. Mayer said he was not speaking for the company.

Hawley and Sanders criticized Boeing for giving recent CEOs substantial compensation packages, but holding out against the IAM's proposals.

"Fairness may be elusive, but that doesn't look like fairness to me," Hawley said.

Boeing's board approved $22 million in compensation for Ortberg in 2025. The IAM estimates its proposal would cost Boeing $40 million a year on average.

(Reporting by Dan Catchpole in Seattle, Editing by Alistair Bell and Nia Williams)