Workers at a Vought Aircraft plant in Nashville who have been on strike since September have been threatened with replacement if they don’t return to work. The 900 employees walked off the job after they rejected the last contract proposal from the company. The company is seeking to stop new payments into an employee pension fund and instead introducing a 401(k) plan. Other issues include overtime benefits and seniority. The workers are represented by the International Association of Machinists who last met with the company on December 12.