From L. A. Times – In-flight confrontations can lead to charges defined as terrorism:
Some security experts say the use of the law by airlines and their employees has run amok, criminalizing incidents that did not start out as a threat to public safety, much less an act of terrorism.
In one case, a couple was arrested after an argument with a flight attendant, who claimed the couple was engaged in “overt sexual activity” — an FBI affidavit said the two were “embracing, kissing and acting in a manner that made other passengers uncomfortable.”
Do not be alarmed. Be very very frightened, Arthur Dent!