What’s the plan, Sam? Why the United States still needs to lead on aviation emissions.

Four years ago, I explained why the United States needs to lead in developing policies to control greenhouse gases from aircraft, owing both to the country’s large share of current emissions and also its history as a heavy polluter. I estimated that the average U.S. citizen consumed about three times as much jet fuel as a typical European, six times that of the global average, and as much as 70 times that of a typical Indian citizen.