The union representing 33,000 striking machinists at Boeing rejected the company's latest contract offer Wednesday evening, extending a strike that has strained aircraft production.The International Association of Machinists and Aerospace Workers (IAM) has been on strike since Sept. 13 as they try to extract more concessions from Boeing in their next labor contract. Earlier this month, the IAM said Boeing offered a 35% wage hike over four years, a new incentive plan and a $7,000 ratification bonus, as well as improved retirement perks.Late Wednesday night, the IAM's ratification vote failed as 64% of its members voted against agreeing to the contract. With the strike set to continue until a deal is reached, assembly lines at Boeing's West Coast facilities are nearly all idled, including production of its best-selling 737 Max, 767, 777/777X, P-8, KC-46A Tanker and E-7 Wedgetail. "We have made tremendous gains in this agreement in many areas our members said were important to them.