Back in July, I pondered whether the airlines' June operating metrics portended a sea change (or perhaps a sky change?) in the industry. Legacy carriers from UAL (NYSE:UAUA) to US Airways (NYSE:LCC) were seen slashing capacity, and fuller, more profitable flights were the clear result.

Low-cost carrier JetBlue (NASDAQ:JBLU) has charted a different course. It has chosen to expand capacity instead -- albeit at a reduced pace as of late -- and third-quarter results suggest that the strategy may be a sound one.

Operating revenue grew at a 22% clip over the prior year. Top-line growth has always been JetBlue's strong suit -- as of June 30, sales at the dynamic discounter had compounded at a 41% five-year annual rate.

The bigger sticking point in recent years has been profitability, but there's good news on that front as well. JetBlue flew roughly 2% fuller flights, even with an 11% boost in the number of seats available. Because revenue per passenger per mile rose more rapidly than expenses on the same basis, the operating margin experienced a big improvement. Net income handily beat expectations, too -- a welcome change from breakeven results in the prior year.

Still, I wouldn't say it's all blue skies for JetBlue at this point. The company carries a substantial debt load, and it's just not the nimble young upstart it once promised to be. Virgin America has hit the scene, and I expect it to be an able competitor. That's the last thing JetBlue needs while it's just regaining its footing.

If you're simply dying to buy an airline today, CAPS players have identified Republic Airways (NASDAQ:RJET) as the only carrier that's five-star material. The balance sheet is no picnic, but Republic's outsized margins are certainly intriguing. Thanks, CAPSketeers -- I'll keep an eye on that one.

Fool contributor Toby Shute doesn't have a position in any company mentioned. JetBlue is a Stock Advisor selection. The Motley Fool has a disclosure policy.