New York Times: Jet fuel is now the largest expense for most airlines, and for American carriers each penny increase in price per gallon costs nearly $200 million a year. The industry is also becoming increasingly nervous about what happens when that fuel is burned. Aviation is responsible for about 2 percent of global emissions of greenhouse gases, and that share will rise as air travel continues to grow.

So the industry is scrambling to build greener airplanes — to save weight and improve engine efficiency, with an eye toward reducing operating costs and emissions.

In the short term, a revolution in jet engines is about to occur, with radically different designs that use gears to cut fuel consumption, noise and pollutants. And those new engines will power planes built more and more with carbon composite materials, which are lighter and may also be safer than the aluminum they replace.

The biggest change with aircraft is electricity: The 777, a mid-1990s design, can generate up to 270 kilowatts of electricity, enough to run a small neighborhood of houses. The 787, would make five times as much, 1.35 megawatts, in order to power a multitude of motors and pumps that help make the place lighter and safer.