Paranoid Airplane

Arrived, jetlagged, in Britain. Lovely to be back.

Have I only recently noticed it, or is it a new phenomenon? I want to know about the visible air released in cabins. What are the legal issues around airlines' decision to not carry more fresh air? What happened to sanitary class-action suits? Everyone knows that everyone gets sick. What would it be like to use the air for warfare? If a hijacker were attacking the plane, for example, to gas everyone but the pilots asleep?