re-engined JN-4H version of the most-produced JN-4 subtype, the final production version of the aircraft was the JN-6, powered by a Wright Aeronautical license-built, 150-hp (112-kW) Hispano-Suiza 8 V-8, first ordered in 1918 for the US Navy. A floatplane version was built for the navy which was so modified, it was essentially a different airframe. This was designated the N-9. In US Army Air Service usage, the JN-4s and JN-6s were configured to the JNS ("S" for "standardized") model. The Jenny remained in service with the US Army until 1927. After World War I, thousands were sold on the civilian market, including one to Charles Lindbergh in May 1923, in which he then soloed. Surplus US Army aircraft were sold (some still in their unopened packing crates) for as little as $50, flooding the market. With private and commercial flying in North America unhampered by regulations concerning their use, pilots found the Jenny's stability and slow speed made it ideal for stunt flying and aerobatic displays in the barnstorming era between the world wars, with the nearly identical Standard J-1 aircraft often used alongside it. Some were still flying into the 1930s. JN-4 airframes were used to produce early Weaver Aircraft Company / Advance Aircraft Company / Waco aircraft, such as the Waco 6. Notable firsts Between 1917 and 1919, the JN-4 type accounted for several significant aviation firsts while in service with the US Army Signal Corps Aviation Section and the United States Marine Corps (USMC) including flying the first US Air Mail in May 1918. In a series of tests conducted at the US Army's Langley Field in Hampton, Virginia, in July and August 1917, the world's first "plane-to-plane" and "ground-to-plane, and vice versa" communications by radiotelephony (as opposed to radiotelegraphy which had been developed earlier) were made to and from modified US Army JN-4s by Western Electric Company (Bell Labs) design engineers Lewis M. Clement and Raymond Heising, the developers of the experimental wind generator-powered airborne wireless voice transmitter and receiver equipment. In early 1919, a United States Marine Corps (USMC) JN-4 was also credited with what is believed to be the first successful dive bombing attack during the United States occupation of Haiti. USMC pilot Lt Lawson H. Sanderson mounted a carbine barrel in front of the windshield of his JN-4 (previously, an unarmed trainer that had a machine gun mounted in the rear cockpit) as