Right now the Rio Olympics opening ceremony appears to be suggesting that the Wright Brothers did not undertake the first human airplane flight? Have I been wrong this entire time?

Who flew first really comes down to how you define an 'airplane.' The Wrights beat out a lot of earlier efforts because of their understanding of the fundamental forces of flight (lift, weight, thrust, drag), as well as their understanding and implementation of aerodynamic control. Their aircraft could fly straight and level, but it could also turn, roll, or climb/descend.

The Wright's Flyer I was rail-launched, however. It used a wooden rail and dolly system to avoid excess friction with the ground. While the Flyer did take off under its own power, the rolling dolly and track stayed on the sand. In their later designs, the Wrights also added a catapult. This reduced the takeoff field length and fuel required, allowing them to spend more time in the air with their crude (then state-of-the-art) engines. Incidentally, the section of Santos-Dumont's 14-bis wiki page devoted to the record is incorrect on one count- there was no catapult in use during the December 17, 1903 flights by the Wrights. There appears to be an edit war occurring within the page regarding the use of the catapult. Photographic records show no catapult. The catapult design was first implemented in 1904, when the Wrights moved their trials to Huffman Prairie, near Dayton.

Many people contend (evidently the Brazilian Olympic Commission falls into this group) that Santos-Dumont should receive credit for the first flight, almost three years after the Wright's Kitty Hawk flight. This is because his aircraft, the 14-bis, was entirely self-contained- it took off under its own power and took its landing gear with it. However, while Santos-Dumont's aircraft might exceed the Wright's first Flyer in it's takeoff integrity, it lacks any provision for roll control, instead relying on a pronounced dihedral (upward bending) of the wings to remain stable along the fuselage's axis. In addition, from the design of the 14-bis it is apparent that a much greater emphasis was placed on the application of proven technology to the airframe than on the use of newly-developed material. The Wrights used airfoils formed to extremely precise dimensions for their propellors and wings. The 14-bis used balloon parts for a great deal of its structure.

Santos-Dumont was of course an important figure in the early years of flight, though he is not so much remembered for his technical contributions as the Wright brothers are for theirs. Santos-Dumont worked with French pioneers to develop the first aircraft for sale, the Demoiselle- this aircraft used wing warping, a Wright-patented method, for roll control. The Demoiselle could be ordered with a Wright engine.

For further reading I'd suggest David McCullough's 'The Wright Brothers.' It gives an accurate but sometimes sepia-tinted account of the Wright's path to their flight, as well as exploring other projects of the time; I believe Langley is mentioned, as is Santos-Dumont.

In addition, if you can get your hands on the Time-Life books 'The Epic of Flight,' those provide an extremely comprehensive overview of the entire history of aviation, starting with the first dirigible flights.

On a personal note, the debates of 'who' 'flew' 'first' are almost always centered around national pride, rather than a serious historical inquiry. Take new 'information' with a grain of salt. A few years ago there was a claim to the title put forth by exponents of Gustav Whitehead that turned out to be complete bunk.