The first claimed powered flight, by Gustave Whitehead in his Number 21.

Aviation includes the activities surrounding mechanical flight and the aircraft industry. Aircraft include fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air aircraft such as hot air balloons and airships.

Gustave Albin Whitehead was a German–American aviation pioneer. Between 1897 and 1915, he designed and built gliders, flying machines, and engines. Controversy surrounds published accounts and Whitehead's own claims that he flew a powered machine successfully several times in 1901 and 1902, predating the first flights by the Wright brothers in 1903.

The Whitehead No.21 was the aircraft that aviation pioneer Gustave Whitehead claimed to have flown near Bridgeport, Connecticut on August 14, 1901. Professional aviation historians and scholars reject claims for the flight. A description and photographs of Whitehead's aircraft appeared in Scientific American in June 1901, stating that the "novel flying machine" had just been completed, and "is now ready for preliminary trials". The flight was reported in the August 18, 1901, issue of the Bridgeport Sunday Herald and reprints or rewrites were published in many other newspapers.

August 14 is the 226th day of the year in the Gregorian calendar; 139 days remain until the end of the year.