At 79, the primary architect of the ultra-low-cost carrier segment of the U.S. airline industry shows no signs of slowing down --- far from it.

Rather, Bill Franke is working on his latest airline: Santiago, Chile-based JetSmart, which is expected to begin flying this fall with a fleet of Airbus A320s, providing point-to-point service involving cities that potentially include Antofagasta, Arica, Calama, Puerto Montt and Punta Arenas as well as Santiago.

Asked if he can be called a serial airline investor, Franke responded, "It's true - -I've invested in seven or eight of them."

Franke is starting JetSmart from scratch. More often, his firm, Phoenix-based Indigo Partners, buys into existing airlines and oversees their transformation into ultra-low-cost carriers. This is what happened at Frontier, which Indigo owns, and before that at Spirit (SAVE) - Get Report , where Indigo Partners was a principal investor between 2000 and 2013.

"Spirit had been running {in} the middle ground," he said. "It made money and then it didn't. We acquired control and changed the model entirely.

"I had been a pre-IPO investor at Ryanair, so I understood the {ULCC} model," he said. "And I had competed against Southwest for many years" as CEO of America West Airlines.

Franke began his airline career at America West, a low-cost, Phoenix-based carrier that was operating under bankruptcy code when he was asked to step in. He worked to restructure the airline and also displayed a talent for hiring developing young executives including Doug Parker, Scott Kirby, Derek Kerr, Robert Isom and Steve Johnson.

A decade later, that team, headed by Parker, had managed to take over management of American (AAL) - Get Report , the world's largest airline.

What does Franke look for?

"We debate that quite a bit," he said. "You have to have somebody who has high energy and who is coachable. The rest you can manage. If a person has their mind made up, and thinks they know it all, they will have a problem. We work hard to find people who are smart, have high energy and accept coaching.

"Parker is one of them," Franke said. "He met all the criteria."

At United (UAL) - Get Report , CEO Oscar Munoz seems to be following part of the Franke playbook, hiring a series of young airline managers, including Kirby and Andrew Levy. Munoz "got one of the guys I used to work with and another one I knew well," Franke said. "Whether it was intentional or not, that seems to have been the result. The stock market likes it."

United shares have gained about 55% since Kirby left American to join the airline on Aug. 29, 2016.

Besides controlling Frontier, Indigo is the biggest investor in the Hungarian carrier Wizz Air and a principal investor in Volaris, Mexico's second-largest carrier. Franke is chairman of the boards of Frontier and Wizz. Indigo was also a founding partner of Singapore budget airline Tiger Airways.

All Indigo carriers operate Airbus fleets, but Franke said, "I'm agnostic about airplanes: We look for the best deal." In the case of JetSmart, he said, "Boeing (BA) - Get Report was very competitive, but they had timeline and delivery issues.

On aircraft manufacturers, "I am agnostic," he said. "I guarantee you I am."

As for the choice to invest in Chile, Franke has long been familiar with the country. Born in College Station, Texas, he grew up in southern South America, attending school in Argentina and Brazil while his family lived in Asuncion, Paraguay. His father was a Latin American specialist in the State Department.

Additionally, for two decades Franke served as a board member at Phelps Dodge, which had mining operations in Chile, where he occasionally visited.

Franke considered the possibility of an ultra-low-cost South American carrier for five years.

"There is no true low-cost carrier in the cone area of South America," he said. "So we began a deliberate process of looking at the opportunity, and we landed on Chile. It has high transparency {and} a good legal system. The governments change with order. A foreigner can own 100% of an airline. We liked what we saw."

Besides running airlines, Franke gives money to universities, including $25 million each to Northern Arizona University, and University of Montana, and about $6 million to Stanford, his alma mater.

He sees little point in retiring.

"I'm in good health," he said. "I can still add and subtract. Everybody sits at home and looks at TV: I don't want to do that, and I don't want to go to the country club and start drinking martinis at 10 a.m."

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.