Southwest Airlines Co. has been profitable for 40 straight years.

Unlike every other major carrier, it has never filed bankruptcy. It has never sacked employees with layoffs, furloughs or pay cuts. It is also the airline with the fewest complaints — just 0.25 per 100,000 passengers last year, according to the Department of Transportation.

I interviewed Kelly for nearly an hour and then heard him speak at the University of Denver last week. His formula is so basic, yet so seldom applied: Take care of employees, employees will take care of customers, customers will take care of the company and its investors.

“People want to come work for Southwest Airlines because they have an awareness of what I’m describing here,” he said. “They want to work for a great company.”

Kelly is living proof that the airline industry doesn’t have to be run the way it does, cutting fares to steal market share and then sticking investors, creditors and employees with all the losses in bankruptcy court.