Is dropping the F-Bomb a First Amendment right?

http://consumerist.com/2012/05/should-an-airline-pilot-be-able-to-determine-if-your-shirt-is-offensive.html

Herewith, the mother of all f-bomb cases:

403 U.S. 15, 91 S.Ct. 1780, 29 L.Ed.2d 284

Briefs and Other Related Documents

Supreme Court of the United States

Paul Robert COHEN, Appellant,
v.
State of CALIFORNIA.

No. 299.Argued Feb. 22, 1971.
Decided June 7, 1971.

The defendant was convicted before the Superior Court of Los Angeles County of the offense of disturbing the peace and he appealed. The Court of Appeal, Second District, 1 Cal.App.3d 94, 81 Cal.Rptr. 503, affirmed the conviction, and the defendant appealed. The Supreme Court, Mr. Justice Harlan, held, inter alia, that conviction of defendant who walked through courthouse corridor wearing jacket bearing the words ‘Fuck the Draft’ in a place where women and children were present of breach of the peace under California statute prohibiting disturbance of the peace by offensive conduct could not be justified either upon theory that the quoted words were inherently likely to cause violent reaction or upon more general assertion that the states, acting as guardians of public morality, may properly remove such offensive word from the public vocabulary since the state may not, consistently with the First and Fourteenth Amendments, make the simple public display involved of the single four-letter expletive a criminal offense.

Reversed.

Quick quiz: what's the distinguishing issue that distinguishes the airline case from the Cohen case?