"I mean, what pilot wouldn't be a tad nervous at having the man who flew to the moon in Apollo 11 sitting next to him."
Bruce believed Armstrong was on holiday with family and friends the day he bowled up unannounced at the natural tourist trap for the trip in a Cessna.
"I know he was a very private man so I didn't want to trouble him for a picture or start pestering him for an autograph," the grandfather-of-three said.
"I also knew that most people are blown away by the sight of Milford Sound, but how do you impress a guy who has been to the moon?"
Bruce said Armstrong sat next to him for the duration of the flight and afterwards told him he loved it.
"I thought a short trip like that would be a ho-hum experience for someone like him but a he said it was one of the best things he'd done in his life, so it so it just shows you how good the trip really is."
Bruce retired from flying in 2009 after piloting about 60,000 people around Milford Sound during more than 30 years.
He is sad that Armstrong is no longer with us, but said memories of the day he took the controls with the space hero in the next seat will stay with him forever.
"He was an absolute gentleman," Bruce added.
- Herald on Sunday