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".

[5] The DTs were taken from the assembly lines at the company's manufacturing plants in Rock Island, Illinois, and Dayton, Ohio, to be modified.

[6] The modified aircraft known as the Douglas World Cruiser (DWC), also was the first major project for Jack Northrop who designed the fuel system for the series.

[5] The four aircraft left Seattle, Washington, on April 6, 1924, flying west, and two of these returned there on September 28 to great acclaim, while one plane had been lost under fog conditions, and another was forced down over the Atlantic and sank (the DWC prototype was then rechristened, and joined the other two in completing the North American leg of the flight).

[14] The company retained its military market and expanded into amphibian airplanes in the late 1920s, also moving its facilities to Clover Field at Santa Monica, California.

By the end of World War II, Douglas had facilities at Santa Monica, El Segundo, Long Beach, and Torrance, California; Tulsa and Midwest City, Oklahoma; and Chicago, Illinois.

During World War II, Douglas joined the BVD (Boeing-Vega-Douglas) consortium to produce the B-17 Flying Fortress.

After the war, Douglas built another Boeing design under license, the B-47 Stratojet turbojet-powered bomber, using a government-owned factory in Marietta, Georgia.

The company produced a number of aircraft including the C-47 Skytrain, the DB-7 (known as the A-20, Havoc or Boston), the SBD Dauntless dive bomber, and the A-26 Invader.

The United States Army Air Forces established 'Project RAND' (Research ANd Development)[21] with the objective of looking into long-range planning of future weapons.

In 1967, the company was struggling to expand production to meet demand for DC-8 and DC-9 airliners and the A-4 Skyhawk military attack aircraft.

The company was also struggling with quality and cash flow problems and DC-10 development costs, as well as shortages due to the Vietnam War.

Donald Wills Douglas Sr. became honorary chairman of the merged company, a post he would hold until his death in 1981.

The last Long Beach-built commercial aircraft, the Boeing 717 (third generation version of the Douglas DC-9), ceased production in May 2006.