Originally known as Clover Field, Santa Monica Airport was the home of the Douglas Aircraft Company, which grew to become the largest aircraft company in Southern California, and was the progenitor of many entities and companies that led to the domination of aerospace in the region. In World War II, the Douglas plant at Santa Monica was one of the principal aircraft plants in Southern California, producing thousands of airplanes and employing as many as 44,000 workers. After the war the company continued expansion of its wartime plants at El Segundo and Long Beach, and merged with McDonnell Aircraft (based in St. Louis, Missouri) in 1967, becoming McDonnell Douglas. That was absorbed by its former competitor, Boeing, in 1997. The original Douglas plant at Santa Monica Airport was closed by the early 1960s, torn down, and redeveloped into an office park.