Greenhouse gases from aviation are entirely unregulated, both in the U.S. and among global institutions.

Global

• Aviation greenhouse gases aren't regulated by the Kyoto Protocol, and weren't addressed in the Copenhagen Accord
  
• The UNFCC has asked the International Civil Aviation Organization to address the issue
• (In the meantime, The European Union is moving ahead, bringing aviation into its emissions trading system by 2012)
  

U.S.A.

• The US Environmental Protection Agency (EPA) has the authority to regulate greenhouse gases.
• After the EPA failed to take any action, in June 2010, a coalition of American environmental NGOs sued the EPA to get it to address pollution from aviation (along with ships and non-road vehicles). You can read a description of the lawsuit, as well as the full complaint (PDF).