True. According to
Wikipedia's page on Harry Houdini:
Wing Commander Harry Cobby wrote in Aircraft in March 1938 that "the first aeroplane flight in the Southern Hemisphere was made on December 9, 1909 by Mr Colin Defries, a Londoner, at Victoria Park Racecourse, Sydney, in a Wilbur Wright aeroplane". Colin Defries was a trained pilot, having learnt to fly in Cannes, France. By modern standards his flight time was minimal, but in 1909 he had accumulated enough to become an instructor. On his first flight he took off, maintained straight and level flight, albeit briefly, and landed safely. His crash landing on his second flight, when he tried to retrieve his hat which was blown off, demonstrated what a momentary lack of attention could cause while flying a Wright Model A.
It is acknowledged by Australian historians[46] and the Aviation Historical Society of Australia that the definition of flight established by the Gorell Committee on behalf of the Aero Club of Great Britain dictates the acceptance of a flight or its rejection, giving Colin Defries credit as the first to make an aeroplane flight in Australia, and the Southern Hemisphere.
In 1965 aviation journalist Stanley Brogden formed the view that the first powered flight in Australia took place at Bolivar in South Australia; the aircraft was a Bleriot monoplane with Fred Custance as the pilot. The flight took place on March 17, 1910. The next day when Houdini took to the air, the Herald newspaper reported Custance's flight, stating it had lasted 5 minutes 25 seconds at a height of between 12 and 15 feet.
Who knows which claim is true? Either way, it doesn't seem like it was anywhere in the Sunshine State.