Christy Williams greets people at the voting check-in table where International Association of Machinists and Aerospace Workers union members picked up their ballot in Maryland Heights, Mo., Sept. 12, 2025, to vote on a negotiated tentative labor agreement that would end their strike against Boeing Defense St. Louis regional operations. St. Louis Post-Dispatch via AP

Several thousand Boeing machinists in the Midwest who assemble military aircraft and weapons voted Thursday to approve a new contract, ending a three-month strike that saw them reject four earlier offers from the company.

The breakthrough five-year labor agreement includes a 24% wage hike across the life of the contract and a $6,000 signing bonus, according to the union representing the 3,200 workers who walked off the job on Aug. 4.

“We’re proud of what our members have fought for together and are ready to get back to building the world’s most advanced military aircraft,” the International Association of Machinists and Aerospace Workers said in a statement.

With their new contract in hand, the machinists are set to return to work Sunday at manufacturing plants in the Missouri cities of St. Louis and St. Charles, as well as in Mascoutah, Illinois. The workers build fighter jets, weapons systems and the U.S. Navy’s first carrier-based unmanned aircraft at those facilities.

Boeing said in a statement that it looks forward to “bringing our full team back together.”

While the strike was smaller than last year's walkout by 33,000 Boeing workers who build commercial jetliners, it still threatened to slow the aerospace company’s efforts to regain its financial footing. Boeing’s Defense, Space & Security division makes up more than a third of its revenue.

Union leaders said talks broke down over pay and retirement benefits, while Boeing argued workers' demands went beyond the Midwest's cost of living. The breakdown in negotiations prompted the Congressional Labor Caucus to send a letter to Boeing CEO Kelly Ortberg, urging the company to return to the bargaining table.

“Boeing Defense workers produce planes and other defense equipment that the United States government and our men and women in uniform rely upon,” the letter said. “These workers are essential to the success of your company, and they deserve a fair contract that reflects their hard work and sacrifices.”

Tensions rose long before the strike, with the workers rejecting a proposed 20% raise over the contract's term and $5,000 ratification bonuses. Boeing responded with an offer that kept the same pay increases but dropped a scheduling rule that limited overtime opportunities. Workers turned that down as well and went on strike the next morning, later rejecting two other company offers.