As viagens aéreas de ambientalistas têm sido um saco de pancadas fácil para especialistas conservadores, embora voar esteja se tornando muito mais fácil de defender. Michael Sivak, pesquisador de transporte da Universidade de Michigan, descobriu que de 1970 para 2010, a quantidade de energia consumida por milha, por passageiro, on an average domestic flight dropped 74 por cento. De 1968 para 2014, the fuel efficiency of new airplanes improved 45 por cento, de acordo com International Council on Clean Transportation (ICCT).
For this good news, we can thank airlines’ obsession with fuel, which accounts for roughly one-third of their expenses. Às Boeing, the world’s largest aircraft manufacturer, there’s a rule of thumb: UMA 1 percent improvement in efficiency adds up to $1 million in fuel savings over the course of a single-aisle plane’s 25-year life span.
How are aircraft manufacturers making planes more efficient? Para iniciantes, they’re continually fine-tuning jet engines to create more thrust, by squeezing hotter, higher-pressure air into the turbines and increasing the flow of air around the jet. Planes are also becoming more aerodynamic with design changes like drag-reducing wingtip fins and a more slippery paint inspired by sharkskin. They’re getting lighter, as manufacturers experiment with new composite materials and shave ounces everywhere from the engine to the onboard entertainment system.
And they’re more crowded: Today the average domestic flight takes off with 84 percent of its seats filled, a partir 70 por cento em 2002, according to federal data. (The number of people flying has been on a steady incline since bottoming out after 9/11 and dipping again following the 2008 recession.) Add up these and other factors and, according to Sivak’s research, you’ll find that flying uses 52 percent less energy than driving does to move one person one mile.