As far as I can tell from a word search, the current versions of the Waxman-Markey (passed by the US House of Representatives) and Kerry-Boxer (being introduced to the US Senate) bills to introduce a cap and trade system, whether by accident or design, would involve a unilateral extension of coverage to include international air and sea transport emissions.
Commenting on this IATA Director General Bisignani, in a speech to the International Aviation Club in Washington DC on 15 September 2009, said:
"The challenge is to align governments on economic measures through ICAO. The way that we are heading now, a flight from New York to London could be triple taxed considering the 2012 inclusion of aviation in the European ETS; the UK Air Passenger Duty which will collect GBP 2.7 billion by 2011; and US cap-and-trade proposals in the Waxman-Markey Bill. This is nonsense. The EU ETS is unilateral, extra-territorial and illegal. The US must be among the countries fighting it, shouting even louder."