Basic etiquette thrown out of the window...when flying

Airlines: You can't wear that - Travel - NBCNews.com: "The First Amendment prohibits government from limiting a person's free-speech rights, but it doesn't apply to rules set by private companies, Larsen says. He notes that government security screeners didn't challenge Guha; private Delta employees did."

In short, since airlines and their planes are private property and not a public space like the courthouse steps, crews can tell you what to wear.

In the early years of jet travel, passengers dressed up and confrontations over clothing were unimaginable. They're still rare — there aren't any precise numbers — but when showdowns happen, they gain more attention as aggrieved passengers complain on the Internet about airline clothing cops. It's unwelcome publicity for airlines, which already rate near the bottom of all industries when it comes to customer satisfaction.