Lockheed Martin Corp. announced a 1,000-job voluntary layoff program to reduce employment in its Aeronautics Division.

The program will be available to mid-level employee groups in seven of the company's U.S. facilities, and comes at a time of reduced defense spending. The Aeronautics Division is Lockheed Martin's largest division, providing about one-third of its revenue, and builds the F-35 fighter plane and other military aircraft.

The layoff is meant to "position Lockheed Martin Aeronautics to be competitive in the future marketplace, secure future business opportunities, and keep an infrastructure appropriately aligned with customer demands," a company statement said.

Lockheed Martin employs about 126,000 people. The affected facilities includes those in Fort Worth, Texas; Marietta, Ga.; Palmdale, Calif.; Meridian, Miss.; Clarksburg, W.Va.; Patuxent River, Md., and Edwards Air Force Base, Calif.