A "Twitter Etiquette" class might just be the answer for the latest tweets surrounding U.S. Airways, American Airlines, and Southwest Airlines.

Let's start with U.S. Airways.  The U.S. airline recently made headlines for a pornographic tweet it posted in response to a customer's complaint on Monday.

U.S. Airways tweeted, "We welcome feedback, Elle. If your travel is complete, you can detail here for review and follow up."

Seems like an appropriate tweet right? Wrong.

Instead of including a link where Elle could actually "review and follow up," U.S. airways attached a link to a photo of a naked women in a sexual position with a toy plane.  Talk about a major OOPS.

To see the NSFW photo, click here.

U.S. Airways apologized for the online obscenity via Twitter, and according to BuzzFeed, the image originated from a German amateur porn site.

Looks like U.S. Airways' employees might need to stop engaging in extracurricular activities during work hours.

American Airlines was also involved in a bit of a Twitter scandal with a 14 year-old Dutch girl named Sarah who threatened the airline via Twitter.

"@AmericanAir hello my name's Ibrahim and I'm from Afghanistan. I'm part of Al Qaida and on June 1st I'm gonna do something really big bye," she tweeted.

American Airlines quickly responded to the terrorist threat and alerted the girl that her IP address and other details would be forwarded to the FBI.

Despite the girl's apology to the Airline and her claim that the tweet was just a joke, police arrested her.

CNN reports that the girl has been charged with "posting a false or alarming announcement" under Dutch law, but the consequences of the accusation remain unclear.

As though Sarah's arrest wasn't warning enough, another Twitter user sent a threat to Southwest Airlines. Southwest Airlines responded to the threat by tweeting, "Your info has been given to the appropriate authorities."

Here's a lesson folks... be careful what you say on Twitter because it may come back to bite you. Twitter Etiquette class, anyone?