Over the next half century, international air travel is expected to as much as triple. But with more flights and more flyers comes a rising environmental and consumer cost to flying.
So what's being done to make air travel more efficient? In the short run, the answer is actually building larger aircraft. The Airbus 380, which is the largest passenger airliner in the world, has actually managed to bring down per passenger fuel use by 20 percent compared to a 747 simply by seating more flyers. The plane is also capable of running on a biofuel blend�which may or may not be impressive depending upon your opinions about biofuels.
In the longer term though, there numerous hybrid and electric airplane concepts that could provide possible alternatives to traditional internal combustion aircraft. Boeing recently presented a design called the SUGAR Volt to NASA as part of the N+3 initiative, whose goal it is to "overcome significant performance and environmental challenges or the benefit of the general public."
The SUGAR Volt is in many ways similar to hybrid vehicle. Twin jet engines are used to power electric motors that in turn supplement those engines, yielding as much as a 70 percent increase in fuel economy. But the principle at play here isn't regenerative braking.
Read More... [Source: HybridCars.com]