Was the Wright brothers December 1903 flight really the first powered, controlled flight of a heavier than air craft?

The Wright Flyer's 1903 flight is the flight most widely credited as first, and it is the best documented of the era, with witnesses, a surviving aircraft and a famous photograph. But rival claims exist: Gustave Whitehead is claimed by some researchers to have flown a powered aircraft in Connecticut in August 1901, over two years earlier, based on a contemporary newspaper account and later witness affidavits gathered decades afterward; mainstream aviation historians and the Smithsonian Institution do not accept the claim, citing the absence of a surviving aircraft, photographs taken in flight, or contemporaneous technical verification. A similar, less publicized claim exists for Richard Pearse in New Zealand around March 1903.