Ford employees at the company’s Iron Mountain plant in Michigan’s Upper Peninsula had a new use for their woodworking skills during World War II, as they went from producing parts like station wagon bodies to building thousands of lightweight wooden gliders for the U.S. Army.

In addition to tanks, jeeps and bombers, Ford was making for the military, the company took on the manufacturing of Waco CG-4A gliders in 1942 at the request of the U.S. government.

Essentially an airplane without a motor or propeller; the gliders were used to deliver troops and cargo to the battlefields where they could make a quiet, stealthy landing. Larger, more capable versions of the aircraft, the CG-13 and CG-13A, were later created, more than doubling passenger space and increasing cargo area.

The first Ford-built glider was built and tested at Ford Airport within five months of the U.S. government’s letter of intent. Ford engineers improved on the original design as well as production procedures and reduced the build time needed. Ford workers produced over 4,000 of the gliders, the most of any facility contracted to build them. The Ford gliders were so efficient that they were used by other plants as a model of interchangeability of parts and assemblies.

Construction of the massive Iron Mountain sawmill complex began 100 years ago this month, after company founder Henry Ford purchased more than 300,000 acres of timberland in order to produce wooden auto parts such as framework, floorboards and wheels. Iron Mountain was also the site of a hydroelectric plant.