Officially known as the "Ryan NYP" (for New York to Paris), the single-engine monoplane was designed by Donald A. Hall of Ryan Airlines and named the "Spirit of St. Louis" in honor of Lindbergh's supporters from the St. Louis Raquette Club in his then hometown of St. Louis, Missouri. To save design time, the NYP was loosely based on the company's 1926 Ryan M-2 mailplane, the main difference being the NYP's 4,000-mile (6,400 km) range. As a nonstandard design, the government assigned it the registration number N-X-211 (for "experimental").