Boeing (BA -2.87%) will build its new 777X airliner in Seattle -- and Boeing workers are giving up their pensions.

Those are the two most important upshots of the vote that Boeing's machinists union, the International Association of Machinists and Aerospace Workers District 751, District W-24, held on Friday. Asked by Boeing to hold a historic vote on its "best and final offer," in which the local union could accept 10 years of average 0.5% annual wage increases, and a switch from defined benefit pensions to defined contribution 401(k) plans, in exchange for guarantees that Boeing would keep production of the 777X in Seattle, the union opted to vote for job security.

By a vote of 51% for, 49% against, the IAMAW agreed to accept Boeing's offer Friday, and ignore union leaders' "adamant" recommendation that they reject the contract. On the plus side, as the union's leadership explained, this "means Boeing will stop seeking alternate sites for its 777X aircraft program, the latest version of its best-selling widebody jet, and start preparations to start final assembly and wing fabrication in Puget Sound."

Boeing confirmed that view: "We're proud to say that together, we'll build the world's next great airplane -- the 777X and its new wing -- right here [in Seattle]. This will put our workforce on the cutting edge of composite technology, while sustaining thousands of local jobs for years to come."