In 2003, he flew more than 5,000 miles in an ultralight with his younger brother, John, to commemorate the centennial of the Wright Brothers' historic first flight.
"It's two brothers from Dayton honoring another two brothers from Dayton," Mr. Gardner said.
The entire flight was a continuous training lesson. Regulations call for ultralight passengers to be considered students taking a lesson. The Wright Brothers tribute involved 58 stops in 19 states, 500 gallons of fuel and 132 hours of flight time over about 3 weeks. The top speed of the ultralight was 75-80 mph.
Mr. Gardner invested years of planning and 900 hours into building his Rans S-12XL Airaile ultralight for the excursion.
"I pulled it off safe, legal, no accidents and no cost to the taxpayer," he said.
He navigated the old-fashioned way, with a compass, charts, landmarks and dead reckoning, instead of a Global Positioning System device.
"That is a feat in itself," the pilot said. "Hardly a pilot in any airport flies without a GPS to find something 20 miles away. Really, not many people can do it, even if their lives depended on it. It's a lost art in the aviation community."
Student pilot Denver McKenzie, 54, of North Augusta, has taken lessons for several months from Mr. Gardner, and he said:
"I've been flying as a student pilot since 1970, but because of finances haven't been able to complete my training until now. Dave is the fourth instructor I've had. He's a very thorough guy that you can understand.
"I have learned what to expect from the aircraft. I also think it's pretty cool that I'm training in the plane he flew coast to coast for his Wright Brothers memorial trip."