The Cunningham-Hall Aircraft Corporation was created in 1928, with Francis E. Cunningham as President and Randolph F. Hall as 2nd Vice President and Chief Engineer. The company did not produce any aircraft from 1931-1934, and 1940-1945. The PT-6, a six-place all-metal cabin biplane, was built from 1928-1930. A four-seat version of the PT-6, the PT-4 was never constructed. During 1935, Cunningham-Hall reemerged to produce the GA-21M, a two-seat monoplane. The GA-21M was based on a high-lift wing design the company had entered in the 1929 Guggenheim Safe Aircraft Competition. A similar version, the GA-36, was introduced in 1936. The next Cunningham-Hall model was the PT-6F, the cargo version of the earlier PT-6. This cargo plane was built only in 1939; by 1940, Cunningham-Hall was involved in defense contract research rather than aircraft production.