"Ben was a great guy and he will be very sorely missed," Prudden told the Herald on Sunday. "He was renowned for his flying expertise and he was also a very capable climber.
"Everyone here is shocked about what happened. Ben loved flying and he had a great sense of humour."
In November 2012 Letham made the news when he was freed from a tree about 60 metres above the ground when he crashed after taking off from the Queenstown gondola.
He had taken off from Bob's Peak during a private solo flight but got into trouble on his decent after a his chute got caught by a tree.
Prudden said Letham - who was in his mid-20s - had also suffered a serious spinal injury in the past but had staged a remarkable recovery to fly again.
Craig Smith from the Southern Hang Gliding and Paragliding Club said Letham had been a popular member of the organisation.
"I knew Ben as a friend and he was mischievous and funny guy," he said. "He was a very experienced pilot and just loved flying. It is so sad."
Another witness said Letham had "flipped and then got tangled".
"It was just one guy by himself, not a tandem," the man said.
"From what I heard he toppled head over heels and from what I can see he has landed on a building and then hit the ground."
It is understood a woman, believed to be Letham's girlfriend, arrived at the scene shortly after the crash.
"As you can imagine it was pretty awful when his girlfriend arrived," the man said.
A witness from Holland told the Otago Daily Times Letham fell for five seconds. "It was really high," she said.