Some people don't understand that "freedom of speech" is NOT an absolute in any and all situations.
A woman was recently asked to leave a Southwest plane because her shirt was lewd and offensive. She claims her freedom of speech was violated.
here's the wtopnews article. The shirt showed Bush and a few of his cronies, and said Meet the F***ers (spoofing the recent movie title).
Firstly, a plane is owned by a company. You want to fly on the plane, you gotta play by their rules. It's not a public location. (That's my opinion, admittedly, I'm not sure how well that would hold up in court)
Secondly, she was told she could stay on the plane if she kept the shirt covered. She failed to do so, and was told that she'd need to change the shirt. She refused, and was given the boot.
Thirdly, in general, you don't have freedom of speech in situations where your speech violates the freedoms of others. If they are able to freely walk away, you can say pretty much whatever you want, but in a classroom, or in a confined space like a plane, offensive materials can be banned. This ruling has held time and again.
So huzzah for the airline!