Unionized factory workers at Boeing are voting on Monday whether to accept a contract offer or to continue their strike. The walkout has lasted more than seven weeks, shut down production of most Boeing passenger planes and cut off a key source of cash for the company. A Seattle-based district of the International Association of Machinists and Aerospace Workers is recommending that its members approve the Boeing offer, which would raise pay rates by 38% over four years. Workers also would receive ratification and productivity bonuses. However, Boeing didn’t meet their demand to restore a pension plan that was frozen nearly a decade ago.