A fact and a figure keep popping to mind as I talk with aviation experts about whether commercial flight can ever go green. The fact is this: Everything you can think of that’s spurring a green revolution on the ground will be of little help in the sky anytime soon. Solar panels, wind turbines, electric engines, high-storage batteries, hydrogen fuel cells, magnetic levitation—they are all, bluntly put, useless at present when it comes to the technological challenge of launching a few hundred people into the stratosphere and carrying them thousands of miles. Here’s the figure: More than 80 percent of humanity has never flown at all.
How this fact and this figure relate to each other is the crux of the problem facing airlines and aircraft manufacturers as they take on the critical task of decarbonizing flight. Aviation can go green, but not soon and not as comprehensively as ground-bound transport. Gravity is a very stubborn thing. Yet how quickly the air travel industry does proceed could affect its image—and bottom line. As environmental advocates warn that flying makes an intolerably large contribution to climate change, the pace of progress in greening the sky may well lead travelers to question whether it’s ethical to fly at all.