Spirit Airlines (Nasdaq: SAVE) is not having a good week on Twitter. First, its ridiculous new checked-bag fees caused Fool Sean Williams to name it in his CEO Gaffe of the Week column. Then, adding insult to injury, a refusal to refund a dying Vietnam vet the price of his ticket when his doctor deemed him too sick to fly is bringing on the outrage.

But Spirit is not the first airline to battle the Twitterverse. And beyond legitimate news of share price, key business decisions, flight delays, and special offers, social media hasn't always been kind to airlines. But will negative tweets translate into a loss for investors?

All my bags are packed, I'm ready to go
 In June 2011, a video made on board a Delta (NYSE: DAL) plane by U.S. soldiers returning from Afghanistan claimed the airline had charged 34 soldiers nearly $3,000 in out-of-pocket fees for excessive baggage, despite an agreement with the Department of Defense. The airline was shredded in the media and on the blogs. Did it hurt? The share price was approximately $11 then, and it's approximately $11 now. Revenue is up approximately $645 million from this time last year. Sure, the stock has had some rough edges, with a severe dip in August, but I have a feeling that has more to do with the general economic climate than any strong anti-Delta sentiment.

United breaks guitars, and loses face
 In 2009, United Airlines' (now United Continental (NYSE: UAL)) stock price fell 10% after a passenger whose expensive guitar was broken by ground crew wrote a song and posted the video to YouTube. It was the first of three videos about the issue and received more than 10 million views. Subsequent videos about the difficulty in resolving the issue with United received about 1.4 million and 400,000 views, respectively.

A 10% drop sounds bad, but keep in mind the stock was trading at $3.34 at the time. It's now hovering around the $22 mark. If you had invested in United pre-merger, despite the broken guitars, you'd be singing a song of your own. Maybe you'd even post it to YouTube.

While apologizing for calling a blogger an idiot, Ryanair calls the blogger an idiot
 In February 2009, an Irish blogger who thought he had found a way to book free tickets on Ryanair (Nasdaq: RYAAY) was mocked and insulted by Ryanair staff, who called him an idiot and a liar with a pathetic life. The airline's spokesperson would only confirm it was not company policy to engage with idiot bloggers. He then went on to call the blogger a lunatic.

Did it hurt? Not too much. Revenue increased from $384 million in March 2009 to $475 million in March 2011, and shares have risen strongly in the past three years.

The crazy uncle of airlines
 While these incidents serve as a valuable reminder, Spirit would be best served to take a hard look at the airline industry's celebrity nightmare, JetBlue (Nasdaq: JBLU). In 2010, a flight attendant, who ironically served on the company's in-flight values program, engaged in a dispute with a customer, used the plane's PA system to scream profanities at him, and then deployed the emergency hatch and sailed to freedom before being arrested. More recently, a pilot had what appeared to be a mental breakdown while flying a routine flight.

JetBlue stock is currently trading at less than $5 a share, the company's debt is more than twice its revenue, and its Twitter feed is filled with apologies for flight delays and other customer complaints.

The Foolish bottom line
 Ultimately, Twitter campaigns won't make or break any of these stocks. Done effectively, such campaigns may prompt an airline response to a particular problem, as it did this week when Spirit CEO Baldanza bowed to media pressure and agreed to refund the dying veteran's airfare, as well as make a contribution to Wounded Warriors in his name. Done ineffectively, tweets, posts, comments, and videos are merely a sounding board for those flying the not-always-friendly skies.

But before investing in an airline, it's a good idea to check its Twitter feed, just to get the pulse of overall customer satisfaction. Don't waste your time with Spirit, though: Its feed doesn't accept or respond to customer comments.