People have attempted to devise a workable flying machine since at least the time of Leonardo da Vinci. Most of the early designs relied on close approximations of birds, using flapping wings. The gliding flight of birds was also observed and some of the more successful early designs sought to produce a device which would carry a human in gliding flight.
A theoretical understanding of the dynamics of flight was first defined in print by Sir George Cayley in 1809, the same year he built and flew a heavier-than-air model. Cayley is also credited with the first fairly successful glider flights carrying humans.
Aeronautically speaking, the middle of the 19th Century was dominated by the visions and efforts of two people, William Henson and John Stringfellow. They were visionaries, to be sure, but they also were practical people, who translated their visions into actual model flying machines, some of which had limited success. All practical efforts to design, build and fly model or actual flying machines owe their origins to the designs of Henson and Stringfellow. They were also the first to propose a commercial enterprise to exploit the flying machine, the Aerial Transit Company. The brilliant publicity of Frederick Marriott ensured that the image of the Henson Aerial Steam Carriage named ARIEL would become familiar around the globe. The proposed commercial passenger-carrying 1849 airship of Rufus Porter was also firmly fixed in the popular imagination through the printed image.
Throughout the last quarter of the 19th Century aerial researchers built and tested models to determine in a scientific manner which designs and which approaches would be most likely to succeed in carrying humans aloft in a heavier-than-air flying machine. Notable among these people were Alphonse Penaud, Horatio Phillips and Lawrence Hargrave.
The huge 1894 Test-Rig of Hiram Maxim and the bat-like flying machines of Clement Ader began to edge toward heavier-than-air flight. Each lacked adequate control mechanisms and each effort was lacking in significant ways, but these two attempts were clear evidence that the day of human-carrying heavier-than-air flight was dawning.
By the mid-1890's it was clear to many interested people that "the problem" of human flight, "Manflight" as it was called, was near to a solution. Some of the glider experiments conducted by Otto Lilienthal and slightly later by Octave Chanute were so strikingly successful that it seemed a certainty that someone would certainly succeed in making a powered, controlled, heavier-than-air flight within a decade. Indeed, Chanute's prediction (made in 1893) that the aerial problem would be solved within ten years was uncannily prophetic.
The remarkable series of experimental "Aerodromes" of Samuel Langley and the impressive machine of Wilhelm Kress stand as two of the most promising of the pre-Wright attempts at heavier-than-air flight. Unfortunately, due to the prolonged, even bitter, dispute between Orville Wright and the Smithsonian Institution over credit for the First Flight and Glenn Curtiss' rebuilding and use of the Langley "Aerodrome A" in 1914, some still hold Samuel Langley's Aerodromes in suspicion, even contempt, a profoundly mistaken view. Wilhelm Kress' great machine may well have flown, but for the eternal and almost universal lack of a proper engine. However, it was to be Wilbur Wright and Orville Wright who would finally discover and then combine all the requisite elements into a successful human-carrying heavier-then-air flying machine.
The success of the Wrights in December of 1903 was not immediately recognized or widely noted. Many experimenters continued to pursue their notions of a heavier-than-air flying machine, believing that they might yet be first to go aloft in such a machine. While many people have suggested and supported candidates other than the Wrights for the title of First To Fly, (notably Clement Ader, Gustave Whitehead, Richard Pearse and Karl Jatho) those claimants have been found lacking, for one reason or another. Significantly, the fundamental issue of controlling a flying machine seems to have been addressed in only the most perfunctory way by most of those who sought to build a successful flying machine. The concrete desire to have positive control of a flying machine and the discovery, through rigorous experimentation and study, of the means to exert it were the factors which separated Wilbur and Orville Wright from all others who tried to build a successful flying machine, and were the basis for their triumph.