You know things are bad for environmental policy when the U.S. and China--usually the main antagonists on climate policy--team up to stop Europe from going greener. That's happening now in the battle over a proposed European Union plan to tackle carbon emissions from air travel.
The crux of the problem is this: although airlines spew a relatively modest 3% of global carbon emissions, that share is taking off fast. From 2005 to 2010, air travel's carbon footprint grew by 11.2%, thanks mostly to an explosion in air travel in the developing world. The fact that international flights often cross multiple countries...