There is also an important warning embedded in his story.
Success does not protect anyone from failure.
JetBlue was one of Neeleman's greatest accomplishments, yet it was also where he experienced one of the most consequential professional setbacks of his life.
He founded the company.
He shaped its culture.
He made it successful.
And then, after a major operational crisis, he lost the CEO position.
The natural response might have been bitterness.
Instead, he built again.
That willingness to begin from zero may be the central thread connecting all five airlines.
Morris Air taught him how to challenge established carriers.
Southwest taught him the power of a strong low-cost model and employee-focused culture.
WestJet gave him experience building an airline in a different country.
JetBlue gave him the opportunity to put his own philosophy into practice on a large scale—and taught him painful lessons about operational complexity.
Azul demonstrated that those principles could be adapted to a huge emerging aviation market.
And Breeze became another attempt to rethink how an airline could connect cities in the modern era.
The five companies were not identical.
Neither were the markets.
But the entrepreneur behind them remained remarkably consistent.
Build something.
Question assumptions.
Listen to customers.
Use technology.
Treat employees well.
And if something fails, start again.
David Neeleman's career ultimately challenges the idea that failure is the opposite of success.
Sometimes failure is simply the tuition.
He left university without a degree.
He was fired from the company he admired.
He was temporarily prevented from starting an airline in the United States.
He eventually lost the CEO job at the airline he founded.
Yet none of those events ended his career.
They became chapters in it.
Today, the most striking number associated with Neeleman may not be his wealth, his salary or even his companies' valuations.
It is five.
Five airlines.
Built or co-founded across several decades.
And behind that number is a person who once struggled to fit into the conventional education system, but discovered that he could build systems of his own.
That may be the real lesson of David Neeleman's story.
The world has a tendency to measure people by the institutions they successfully pass through: schools, universities, corporations and titles.
Neeleman's life offers a different possibility.
Sometimes the person who looks unsuccessful inside one system is simply someone whose talents have not yet found the right system.
He did not finish college.
He did not remain CEO of the company he founded.
He did not avoid failure.
He simply refused to let any of those things be the final chapter.
When one airline ended, another began.
When one opportunity disappeared, he found another country.
When a company he created eventually moved on without him, he created something new.
And decades after leaving college without a degree, David Neeleman had done something far more difficult than passing a standardized test.
He had repeatedly built airlines from nothing.
Five times.
And the story was never really about the credentials he did not have.
It was about what he could build with the abilities he did.