We're in another of those times when it's no fun to be in the airline business. By comparison, I guess the Great Depression was worse than trying to cope with fuel costs almost doubling in a year. In more modern times, the 1990-91 recession and the 2000-01 downturn followed by the 9/11 attacks were pretty grim.

So maybe it was no surprise that Herb Kelleher would be so jovial last month, when he and I talked on the day he retired as chairman of Southwest Airlines after 41 years with the company. After all, the legendary drinker and smoker could play golf every day now if he wished. (Unlike your standard-issue CEO, he never had much interest in the game, except to show up at company golf tournaments and make a spectacle of himself with his limited skills.)

But in fact, Kelleher is going to continue working for Southwest, doing whatever his successor, Gary C. Kelly, asks him to do. The only difference, Kelleher said, will be a five-day rather than a seven-day workweek, giving him time to "go to a store, or take the dog to the vet" on a Saturday.

The main reason Kelleher was so cheerful - or "sanguine" as he put it - is that he leaves a superb management team that he helped nurture, running the most financially sound airline in the business. The notion that it all might fall apart without him at the helm is simply preposterous.

Kelleher always has been able to change instantly from jokester to numbers nerd when asked about Southwest's financial strategy. He said much the same last month that he did in our first interview 18 years ago. "We've always been very conservative in respect to our financial strength," he said last month. "We have the best balance sheet. It is a battle now, but we're in pretty good shape to fight this battle."

Kelleher's good cheer runs even deeper than that. He never thought of running Southwest as just a job. It's been a mission: Provide good jobs in a great working atmosphere, which leads to good service to customers, who return the favor by returning again and again. Sounds like a successful strategy for any business, doesn't it?

But few other companies work as hard as Southwest on its corporate culture, talking about it constantly and keeping it in the forefront of employees' minds. Most of those employees were hired in the first place, out of thousands of eager applicants annually, because of their flexibility, sense of humor and willingness to work hard. Their immersion in the culture - and genuine love for the company - is on display every time I encounter a Southwest skycap, gate agent, flight attendant or pilot.

How else can you explain Southwest's pilots spending thousands of their own dollars on a full-page ad in USA Today when Kelleher retired, praising his leadership?

Analysts like to point out that many other factors contribute to Southwest's success. It flies only one type of jet, keeping maintenance and training costs down. It doesn't route every flight through congested hubs, minimizing time on the ground. It anticipated higher fuel costs and bought hedging contracts that have saved it millions. It gained a market foothold in its early days by using older, close-in airports that other carriers could not or would not use.

But in my mind, none of that is as important as Southwest's people. And the contrast could not be sharper between what those people and many employees at other airlines think of their bosses.

On the day Kelleher retired, a few miles away at American Airlines' annual meeting, pilots and flight attendants were outside picketing, calling for the heads of the top five executives.

On Friday, US Airways and United Airlines said they were no longer talking merger. One reason was the challenge of trying to integrate the pilot workforces at the two carriers, a task US Airways hasn't been able to complete with its employees from the old America West.

Is it any wonder that Southwest has a market value today that's five to 20 times greater than any other major airline?