FILE PHOTO: Workers display picket signs, as they protest during a walkout by members of the International Association of Machinists and Aerospace Workers (IAM) over contract negotiations, outside Boeing company's facility, in Berkeley, Missouri, U.S., August 4, 2025 REUTERS/Lawrence Bryant/File Photo

By Dan Catchpole

(Reuters) -Boeing and officials of the striking machinists union are slated to resume contract negotiations on Monday, the company and union confirmed Friday.

Roughly 3,200 members of the International Association of Machinists and Aerospace Workers (IAM) went on strike at Boeing Defense's St. Louis-area facilities on August 4 after rejecting the company's four-year contract offer. They assemble Boeing's F-15 and F/A-18 fighters, the T-7 trainer jet, munitions, and wing sections for the company's commercial 777X jet.

The company has managed to maintain production, flight testing and other work so far using non-union workers, Boeing Defense spokesperson Didi VanNierop said.

On Thursday, top machinists union officials and U.S. Representative Wesley Bell, a Missouri Democrat, walked a picket line with striking workers, pressing the company for a contract closer to an agreement reached last year with its Seattle-area workers.

Boeing's top St. Louis executive, Dan Gillian, responded with a statement on Thursday defending the offer rejected by IAM District 837 members, saying, "Our offer was strong then and is strong now with an average of 40% wage growth.”

Workers want a contract offer with higher general wage increases, faster wage scale progression, and improvements to the company's 401(k) retirement plan, IAM International President Brian Bryant told Reuters on Thursday.

Bryant was among the union leaders who joined workers in picketing, along with Bell, whose congressional district includes many of the workers.

The offer rejected by St. Louis-area workers included a 20% general wage increase, a $5,000 ratification bonus and more vacation time and sick leave. At the time, Boeing said the bonus would not be offered again if that offer was rejected.

The threat "disrespected" District 837 members, Bryant said. "I'm a little pissed off right now."

Last November, the roughly 33,000 members of the IAM District 751, who assemble most of Boeing's jetliners in the Northwest, ended a seven-week strike when they approved a four-year contract that included a 38% general wage increase, higher retirement plan contributions, restoration of an annual bonus, a $12,000 signing bonus, and a pledge to build Boeing's next commercial jet in the Seattle area, if the program is launched within the contract's duration.

Boeing's defense division is expanding manufacturing facilities in the St. Louis area for the new U.S. Air Force fighter jet, the F-47A, after it won the contract this year.

(Reporting by Dan Catchpole in Seattle, Editing by Franklin Paul and David Gregorio)