On October 5, 1905, Wilbur Wright flew the Wright Flyer III for 39 minutes and 23 seconds over Huffman Prairie near Dayton, Ohio, covering about 24.5 miles, which is 39 laps of the field, and he landed because the fuel ran out rather than because anything else stopped him. The record stood until 1908. Orville had made the first powered flight at Kitty Hawk on December 17, 1903, less than two years earlier.
The gap between those two dates is the whole story. In 1903 the machine flew 120 feet in 12 seconds, in a straight line, in wind, once. By the end of 1905 the brothers had flown 38 kilometres in a single flight, had taken passengers, and had written to the War Department offering to sell them a machine. What changed was control.
The 1903 aircraft had a forward elevator and a rudder working against wing-warping, and it was unstable in pitch and tended to slide. The Flyer III, rebuilt in the summer of 1905 with a larger elevator set further forward and the vertical surfaces separated from it, could be flown through a turn without the pilot fighting it. They also fitted a control that let him adjust the warp and the rudder independently, which is what made a banked turn possible.
They kept it quiet. Nobody in Europe believed the claims, and the brothers refused to fly in public unless a contract was signed first, on the grounds that showing the machine would teach competitors everything they knew. Their patent, granted in 1906, was on the control system rather than on any single part, and it is the reason the American industry spent years in litigation while European aviation went ahead.
The public flights everyone remembers came in 1908, when Wilbur flew at Le Mans and Orville at Fort Myer, and the crowds and the newspapers finally accepted what the brothers had been doing in a cow pasture for five years. Orville's flight at Fort Myer in September 1908 killed his passenger, Thomas Selfridge, the first fatality in a powered aeroplane.