Mark it down in the annals of corporate American history. On July 3, 2007, Southwest Airlines Co. officially turned middle-aged.

That's the day that the airline built on buxom tops, lanky legs, hot pants and go-go boots told a 23-year-old college student that she was too scantily dressed to fly.

Blow out the candles. The company that espoused "free love" when it battled to open up Love Field has gone moralistic.

When flights began out of Love Field in 1971, chief executive Lamar Muse offered no pretense of being wholesome or giving a rat's nose about offending anyone. Southwest was selling sex to businessmen – albeit of the voyeur variety – and proud of it.

An airline that carries 96 million customers a year plays to a much larger audience. So now Southwest feels it must protect us from society's rampant poor judgment in attire.

Oddly, as its Old Guard retires, Southwest's corporate mentality seems to be aging.

If Southwest had been responding to a passenger complaint, you've got to wonder why it didn't just say, "Cool your jets. It's a 70-minute flight to Tucson."

And if you're wondering why it took Ms. Ebbert so long to come forward, it took the airline six weeks and two days to reply to her mother's request for an explanation. Not exactly the quick turnaround time that Southwest boasts about.

In its eventual letter to her, the airline explained that "there were concerns about the revealing nature" of Kyla's outfit and that the airline had the right to remove any passenger "whose clothing is lewd, obscene or patently offensive."

A spokesman confirmed that those phrases were included in its letter.

A pot-bellied male in plaid shorts, black socks and sandals or a teenager with shorts pulled so low that he can't walk without holding his crotch is "patently offensive" in my book. But I doubt that anyone fitting those descriptions has been told to straighten up and fly right.

If Southwest found something else worrisome about Ms. Ebbert, it isn't talking, so we have to rely on her accounts.

Every company makes faux pas. It's how it deals with them that sets a company apart. Once Southwest realized that it had stepped in it in the public view, I expected more imagination and less reserve.

An adolescent Southwest might have held a come-as-you-dare contest with prizes for those who pushed the fashion envelope without exposing too much content.

Rather, Southwest showed utter corporate responsibility.

Undoubtedly, the airline's response was crafted by its lawyers or someone thinking like one: "Thou shalt not apologize or make light because that might be construed as guilt when she sues us."

Yes, Ms. Ebbert is contemplating legal action – although it's hard to figure what permanent damage she's suffered.

And yes, her overexposure on national TV shows suggests ulterior motives.

Regardless, a less mature Southwest might have sent Ms. Ebbert yellow Texas roses with a roundtrip pass via a messenger in a Speedo and a muscle shirt. That guy in hot tanks might have been the Herbster himself. Talk about a sight to be left unseen.

Better yet, it would have hired her as a flight attendant.

I guess it's no surprise that a 30-something Southwest is growing up. But, like the aging face in my mirror, I don't have to like it.

I've known Herb Kelleher and Colleen Barrett since the earliest days and feel lucky to call them friends.

I've been asked for the skinny behind their scheduled departure next year. I've kept my suspicions quiet, but now they've been confirmed.

Southwest Airlines is middle-aged. And they never want to be that long in the tooth.