At just 25, Jordan Kean, of Mainland Air, at Momona, is the youngest pilot in New Zealand to hold a category A flight instructor rating.
"Basically, it's the top level of instructor," he said.
He is now eligible to be a general aviation flight examiner, allowing him to issue private pilots' licences and conduct instrument rating renewals, along with instructor renewals.
Mr Kean said he prepared for the two-day assessment by working for four weeks with John Penno, who has held a category A rating for about 30 years.
The test included flying on the first day, followed by assessments on law, documentation and the physics of flight, he said.
"I thought it'd be the hardest thing in the world, and it was.
"I feel great. It's a very humbling experience."
The rating required at least 1250 hours in aeroplanes, as well as 1000 hours as pilot in command and 750 hours instructional time.
While the sky is now the limit for Mr Kean, the son of Mainland Air chief executive Phil Kean, he plans to stay as an instructor with the Dunedin company for a few years yet and work with its 40 students.
Civil Aviation Authority personnel and flight training manager Rob Scriven said Mr Kean was New Zealand's youngest category A instructor. The next youngest was 28.
"Although it is not unprecedented for a flying instructor to get their A-category rating while in their mid-20s, it is still a significant achievement," Mr Scriven said.