Congressional Research Service
http://opencrs.com/document/R42392/
[From Summary] …Air carriers from the United States and other countries have vociferously objected to inclusion of international aviation in the EU ETS. The U.S. government and other nations have pressed the EU to exclude foreign carriers. Two bills in Congress address the controversy. The U.S. House of Representatives passed H.R. 2594, the European Union Emissions Trading Scheme Prohibition Act of 2011. It would prohibit U.S. aircraft operators from participating in the EU ETS. It also
would direct the Administration to negotiate and take other actions to ensure that U.S. civil aircraft operators are not penalized by any unilateral EU regulation of GHG emissions. A similar bill with more flexibility, S. 1956, was introduced in the Senate. In January 2012, House and Senate conferees on reauthorization of the Federal Aviation Administration (FAA) agreed to a sense of the Congress resolution opposing the EU action.