During this period, Syd Chaplin's most important contribution may be in the field of aviation. In May 1919, he, along with pilot Emery Rogers, developed and launched the first privately owned domestic American airline, the Syd Chaplin Airline Company, based in Santa Monica, California. Although the corporation lasted only a year, in that time it established many "firsts." Syd and partners had the first airplane showroom for their Curtiss airplanes. Emery Rogers conducted the first roundtrip Los Angeles to San Francisco flight in one 24-hour period. Charlie Chaplin took his first airplane flight in one of Syd's planes, as did many other notable figures of the period. Syd Chaplin got out of the aviation business after governments began to pass legislation regulating pilot licensing and the taxation of planes and flights.