Next time you feel guilty about booking a flight when you could have driven, cut yourself some slack: in many cases, flying may be the more environmentally sustainable choice.
New research by Michael Sivak of the University of Michigan Transportation Research Institute suggests that the energy expended per person is often higher when driving than when flying the same distance—more than two times higher on average, the Washington Post reports. This calculation depends on the energy efficiency of the vehicles involved, as well as on the fact that passenger planes are often crowded, dividing the necessary fuel among many people. On the other hand, drivers are often alone.
It’s important to note that most of the time, drivers are only traveling short distances, while flyers are traveling long ones—so the overall impact of drivers vs. flyers isn’t a clean comparison.