Fossil fuels could go the way of the dinosaur as airlines scramble to fly on everything from coconut oil to algae. But that kind of evolution won't happen overnight, according to one analyst. "We're at least five years away from alt-fuels being anything but a publicity stunt," says John Scholle, an economist with Global Insight. And while a more modern ATC system is also years away, airlines continue to improve their track record of increased fuel efficiency and reduced greenhouse gas emissions. "Airlines are already motivated to reduce fuel burn and the resulting greenhouse gases as much as possible," says Nancy Young, ATA vice president of environmental affairs.