sentences:  In an era of large, expensive, open-cockpit biplanes, the Monocoupe was the first popular, compact, enclosed-cabin, two-seat, light plane in the United States.As a result, the Monocoupe soon became one of the most popular and successful brands of airplanes in American air races of the 1920s and 1930s.Central States Airplane Company was established in 1927 to build Don A. Luscombe's Monocoupe.