John Stringfellow, who had grown up in the lace and carriage building industries, had a real appreciation for machines, and most especially for steam engines. He became intimately familiar with the oddities of steam powerplants and demonstrated a remarkable ability at designing and building light steam engines. Within a short time after William S. Henson patented his design for the "ARIEL" Aerial Steam Carriage in 1842, John Stringfellow became his associate. It's possible that Henson went looking for someone skilled in steam engine design and fabrication and thus found Stringfellow, for Henson's skill was in engineering and design, not fabrication.
Along with Frederick Marriott and D. E. Colombine, Henson and Stringfellow incorporated the Aerial Transit Company in 1843, to build and operate a passenger-carrying version of the "ARIEL." Their first large model "ARIEL" failed to fly and they went on, over the course of almost two years, to construct a larger version with a 20 foot wing span. Between 1844 and 1847 Henson and Stringfellow made a series of attempts to fly their "ARIEL" models but they simply did not fly. In 1848 Henson left the enterprise and moved with his wife and family to the U.S., leaving Stringfellow to pursue aeronautical research on his own.
The first result of Stringfellow's efforts was the 1848 machine shown below, which was powered by two contra-rotating propellers driven by one of Stringfellow's powerful and lightweight steam engines. The first attempt to fly the 10 foot wing span machine took place indoors, and a lack of proper balance resulted in a failure and damage to the machine. The second attempt was a rather wonderful success, for the flying machine left a guide wire and flew straight and true for about 30 feet.
John Stringfellow and his son Frederick J. Stringfellow collaborated on the experiments and built a number of flying machines together and individually. Perhaps the most famous of John Stringfellow's machines was his steam powered triplane of 1868, which was exhibited at the Crystal Palace in London, England. The superimposition of wing surfaces was an idea which Stringfellow borrowed from Francis Wenham. Except for the lack of a vertical tail surface, it is the very image of an early aeroplane. It was tested a number of times while at the Crystal Palace and did, on occasion, manage to leave the guide wire and fly for a distance. This very flying machine (the steam engine of which won first prize at the Crystal Palace exhibition) is on display in the Early Flight Gallery of the National Air & Space Museum, Washington, D. C. Frederick J. Stringfellow built his own flying machine in 1868 also, a steam powered twin-propeller tandem-winged monoplane, and it too was displayed at the Crystal Palace.
John Stringfellow had planned to eventually build a flying machine which would carry him aloft, and equipped a building for just that purpose. Age and illness intervened, however, and that machine was not built.