Say it ain't so, Southwest Airlines (NYSE:LUV).

Once upon a time, you were the darling of the aircraft industry. The one company not only made a profit but also cared about your customers. Friend to Everyman, you didn't reserve seats, hewing to a first-come, first-served system. Unlike carriers such as Delta (NYSE:DAL) or Continental (NYSE:CAL), you didn't charge for checking baggage -- and you had a sense of humor about it. Who could not love LUV?

Which made it all the more strange when you so unceremoniously escorted Generation-X's "biggest" hero, professional funnyman Kevin Smith, off a plane over the weekend. (We kid because we love, Kev.)

Southwest's big mistake
So here's the story. Booking a flight on Southwest Saturday, Smith adhered to company policy for persons of his girth, by buying two tickets on a particular flight. But Smith also put himself on the standby list for an earlier flight. He got "lucky" and snagged the seat, but after he took it, the pilot determined that Smith needed more than one seat to fly safely. Smith was therefore taken off the plane.

Oh, no!
Oh, yes. Southwest would have been better off banning Warren Buffett over fears he might break a hip, or denying Madonna a seat on suspicion of international baby-smuggling, than antagonizing Smith. Because this is when things got really ugly. Over the ensuing hours, Smith let loose a Twitter-borne tirade against the company, relentlessly needling the company over its "customers of size" policy.

Exit, stage wrong
Compounding its gaffe, Southwest offered Smith a $100 voucher to compensate him for his troubles.

That was, of course, the exact wrong tack to take with Smith. A smarter company, and one with a bit of personality -- one like ... well, the company we all thought Southwest was ­-- might have laughed the incident off. Offered Smith a jumbo-sized Whitman's Sampler and a Valentine's Day card: "Honey, I shrunk the seats. No hard feelings?"

Opportunity, lost
No such luck. Instead, Southwest's $100 offer bought itself a world of trouble. Before the weekend was out, the National Association to Advance Fat Acceptance was calling for a boycott of Southwest, and suggesting Smith's fans switch to a more accommodating carrier.

(Hey, AMR (NYSE:AMR), UAL (NASDAQ:UAUA), and US Airways (NYSE:LCC). That's your cue.)

Driving the point home, Smith promptly tweeted: "Dear Other Airlines (including Oceanic, sans Flight 815): I'm in the market for a flight east this Thurs. Which one of you likes fat people?"

More importantly: Which of you hates PR disasters, and would like a chance to kick Southwest while it's down?

Fool contributor Rich Smith does not own shares of any company named above. The Motley Fool has a disclosure policy, and trial members of any Fool newsletter can fly free for 30 days.