Achievements and claims to precedence over the Wright brothers
From August through November 1903, Jatho made progressively longer hops in a pusher triplane, then biplane, at Vahrenwalder Heide outside of Hanover. His first flight was only 18 meters at about 1 meter altitude. Sources differ whether his aircraft was controlled. The earliest contemporary source suggesting that it was controlled, a newspaper article from Hannoverscher Courier dating 1 August 1907, states that Jatho "has been working on controllable air vehicles for 12 years by now", however a legal document dated 19 November 1902 appears to describe a design that still lacked a controlling mechanism. 30 years after his first flight tests, four eyewitnesses gave a legal testimony certified by a civil law notary in 1933 to having observed his August 1903 flight and that the given data was correct. According to Heimatforscher Wolfgang Leonhardt quoting from Jathos's notes as well as NDR Fernsehen journalist Gunter Hartung, by November 1903 Jatho had managed to achieve a continuous flight of 60 meters at 2.5 meters altitude, a month prior to the 17 December 1903 pioneer flight of the Wright brothers only spanning a distance of 37 meters or 120 feet. Jatho eventually gave up, noting "In spite of many efforts, cannot make longer or higher flights. Motor weak." With a later machine, Jatho would make successful flights in 1909 – 60 meters at about at 3–4 meters altitude. He also founded a flying school and an aircraft factory, but did not have much success.
Later assessments of claims and recreation attempts
Although in Germany some enthusiasts credit him with making the first airplane flight, according to modern researchers such as Leonhardt and Lohmann, Jatho's personal claim to a place in the history books of aviation on grounds of significant pioneer motorized flights of 18 meters in August and 60 meters in November 1903 prior to the Brothers Wright is tarnished by the fact that he took 30 years to have it legally certified by original eyewitness accounts. In the summer of 1933, Jatho's former assistant Werner Hegge attempted to give practical proof by a flight demonstration with an exact replica of Jatho's original machine, but according to the 9 October 1933 issue of the local Hannoversche Kurier newspaper, the weather did not allow for a safe start on the scheduled date. From 1936 onwards, Hegge's replica became a public exhibit at the Deutsche Luftfahrtsammlung Berlin, where it was destroyed during WWII. In September 2006, a local initiative of aviation history researchers and replica builders led by Harald Lohmann attempted another recreation with a new replica in order to bolster credence to Jatho's original claims, but again, adverse weather conditions prevented a successful start, although the replica did achieve successful ground speed that in theory would have allowed for a lift off had it not been for the strong winds on the day of the test. The team decided to wait for better weather conditions, but the legal owner of their replica, Flughafen Hannover-Langenhagen GmbH that had sponsored the building of the replica, did not allow for further tests, as the airport owner instead preferred to make it a permanent exhibit at its Welt der Luftfahrt exhibition located at the airport.
