Mr Underhill took his glider up for about 20 minutes, finding currents of air to keep him aloft before a successful landing at Kybong Airport, near Gympie.
"I haven't been involved with the aviation at all for about 12 years, so it was a little bit like coming home," he said.
"It was very nice, a great feeling.
"For Christmas, my wife gave me an experience flight and gliding up at Gympie, so we went up there and it just reignited my interest."
The 73-year-old said it was a unique feeling being in a glider.
"Gliders are special because of the silence and the efficiency of them," he said.