The Kansas City B-25 Factory

This hastily constructed plant produced 6,608 bombers during World War II

Workers test one of the B-25’s .50 caliber Browning machine guns. Each gun was test-fired with a minimum of 25 rounds.
On December 2, 1940, North American Aviation, Inc. president Dutch Kindelberger visited the existing airport at the Fairfax site and a nearby 75-acre alfalfa field, and telegraphed the following: “Have inspected Fairfax site and it is okay. Airport small but suitable for immediate needs with improvements.” In just 13 months, a factory was erected, employees were hired and trained, equipment was installed, and the first B-25 completed. The main factory is on the left, while the Modification Center is visible on the right.
The assembly line, circa 1944. After leaving the factory, the aircraft were taken to the paint hangar for washing and application of external markings, including insignia and the serial number, which was applied to the vertical tail.
Employees and supplies moved quickly around the sprawling assembly bays thanks to motorized transports.
The Kansas City plant was intended for final assembly, and relied on the arrival of subassemblies from vendors like Fisher Body, a component of General Motors, located in Memphis, Tennessee. Problems with ill-fitting parts were encountered, however; production rates improved when the number of parts fabricated in-plant was increased. Here, workers assemble the wing skin.
Students learned to rivet at the Lathrop Training School in Kansas City, Missouri. Multiple off-site locations were used to prepare employees, who were paid an entry-level wage of 60 cents an hour while in training, and were required to buy their own hand tools.
Flight ramp mechanics read late-breaking details of the D-Day invasion. General Dwight Eisenhower was transported across the English Channel in a modified B-25J built at Kansas City.
Mechanics continue working in spite of floodwaters from the adjacent Missouri River flowing onto the ramp. Each crew, consisting of a crew chief and three to five mechanics, was responsible for three planes.
These ceiling-mounted wing conveyors improved automation and efficiency. The assembly line was not in continuous motion; it was periodically “pulsed,” and the entire lineup of airplanes would be moved forward one position.
The Kansas City B-25 factory was awarded the Army-Navy “E” (for excellence) award in October 1944. Thousands attended the outdoor award ceremony, which included speeches and an Army band playing patriotic tunes.

Throughout the 1930s, airplanes were generally built one at a time, which limited output. Automobiles, however, were mass-produced on assembly lines, and when war came, the nation turned to car manufacturers to help speed up the process.

In 1940, with Europe embroiled in war, President Franklin Delano Roosevelt requested that “this nation [gear] up to the ability to turn out at least 50,000 planes a year,” and asked Congress for a significant increase in defense spending. The National Defense Advisory Committee determined that massive expansion of factory space and workforce would be essential to achieve this goal.

Among the visionaries on the committee was auto industry executive William Knudsen, whose challenge was to apply assembly line techniques to aircraft building. The committee decided that new plants should be constructed in middle America. Multiple cities were selected so that housing, transportation, and other urban infrastructures would not be overwhelmed. The Kansas City plant would be located at an existing airport on the banks of the Missouri River, in the Fairfax industrial district. It would be funded and built by the government, but would be operated under the name North American Aviation, Inc., of Kansas, which was sometimes abbreviated to NAA-K. 

Consistent with aircraft plants then under construction, the Kansas City plant was built of steel and concrete without windows so work could continue in blackout conditions, making it necessary to air-condition the massive building. Constant temperature would minimize expansion and contraction of metal, ensuring a better fit. 

In four short years, it was over. B-25 production was abruptly halted on August 17, 1945, when it became evident that the capitulation of the Japanese was imminent. In November 1945, the official North American Aviation, Inc. of Kansas workforce would number zero. On December 1, 1945, General Motors took occupancy of the vacated plant. The first automobile rolled off the line in June 1946.

Browse the gallery, above, to see images from the wartime B-25 factory.

Text and images adapted with permission from Kansas City B-25 Factory, by John Fredrickson and John Roper. Available from the publisher online, or by calling 888-313-2665.

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