Sept. 12 (UPI) -- More than 3,000 Boeing Co. machinists in St. Louis remain on strike after rejecting the latest contract offer from the aerospace company that seeks to end the strike that began on Aug. 4. The defense contractor's machinists rejected Boeing's third contract offer on Friday and instead will continue the first walkout in nearly 30 years at the Missouri facility, CNBC reported . "Boeing's modified offer did not include a sufficient signing bonus relative to what other Boeing