The assembly line in the Douglas Aircraft plant where wings are attached to the fuselage of big C-54 planes, as seen on July 7, 1944. The plant was located on the future site of O’Hare International Airport. The Douglas Aircraft Company was an American aerospace and defense company based in Southern California. Founded in 1921 by Donald Wills Douglas Sr., it merged with McDonnell Aircraft in 1967 to form McDonnell Douglas, where it operated as a division. McDonnell Douglas merged with Boeing in 1997. History 1920s The company was founded as the Douglas Company by Donald Wills Douglas Sr. on July 22, 1921, in Santa Monica, California, following dissolution of the Davis-Douglas Company. An early claim to fame was the first circumnavigation of the world by air in Douglas airplanes in 1924. In 1923, the U.S. Army Air Service was interested in carrying out a mission to circumnavigate the Earth for the first time by aircraft, a program called "World Flight". Donald Douglas ...