Side A: Interest in the new field of aeronautics grew dramatically when the United States entered the World War I in 1917. The army chose Dayton as the site for a research-and-development program for military aviation because of the area’s transportation links to major cities and its engineering and testing facilities. McCook Field, north of downtown between Keowee Street and the Great Miami River, was charged with researching, developing, and testing military airplanes and accessories. For nearly a decade, many advancements in aviation occurred at McCook Field. They included new aircraft, controllable-pitch propellers, bulletproof gas tanks, free-fall parachutes, and night-observation cameras. In the 1920s, larger and more-powerful aircraft overwhelmed the small field, which featured a large sign to warn pilots: “This field is small. Use it all.” In 1927, aeronautical engineering was transferred to newly-created Wright Field, now a part of Wright-Patterson Air Force Base.