Pratt & Whitney has a more efficient jet engine under development that would be 50% quieter and 50% less polluting and use nearly 15% less fuel, in part because the engine would be made of lighter materials than today's engines. Maintenance costs also would be 40% lower because of a simplified design using about 30% fewer parts. The new engines are unlikely to be ready before 2015.
Easyjet is one of companies making a big push for more fuel efficient jets
Scientific American talks about a superconductor enabled all electric airplane concept However, this idea looks like it needs some more breakthroughs with superconductors and fuel cells or in nanotechnology before it gets off the ground.