The 805th Engineer Aviation Battalion was an American "Arms and Services with the Army Air Forces" unit activated on 12 February 1941 at MacDill Field near Tampa, Florida.

After the German invasion of Poland demonstrated the value of such an organization, the War Department created the 21st Engineers (Aviation) Regiment at Fort Benning, Ga., on June 4, 1940.

As the possibility of American involvement in a global war grew, the planners agreed to give the air forces enough men and equipment to construct their own heavy duty bases in forward areas.

Originally established with 27 engineer officers and 761 enlisted men, a battalion would be capable of "independently constructing an advanced airdrome and all appurtenances."

Standard equipment for battalion deployment included diesel tractors, bulldozers, carry-all scrapers, graders, gasoline shovels, rollers, mixers, air compressors, drills, trucks, trailers, asphalting and concreting equipment, rock crushers, draglines, and pumps.