NASA has unveiled concepts of future, eco-friendly aircraft.

The stunningly innovative designs, which NASA calls greener flying machines for the year 2025, are being developed by three firms under contract to the NASA Aeronautics Research Mission Directorate's Environmentally Responsible Aviation (ERA) Project.

The target is to create designs that consume 50 percent less fuel than aircraft unveiled in 1998, with 50 percent less harmful emissions, and to shrink the size of geographic areas hit by high levels of airport noise by 83 percent, a NASA statement said.

The real challenge is we want to accomplish all these things simultaneously. It's never been done before. We looked at some very difficult metrics and tried to push all those metrics down at the same time, said Fay Collier, ERA project manager.

The Boeing Company in Huntington Beach, California, Lockheed Martin in Palmdale, California, and Northrop Grumman in El Segundo, California, have been engaged in the research and development of the new designs. The expert teams spent the whole of 2011 devising ways to develop the supermodels that meet all the desired goals.

We'll be digesting the three studies and we'll be looking into what to do next, Collier added.

Going by initial indications, the preliminary designs all met the pollution goal of reducing landing and takeoff emissions of nitrogen oxides by a half over engines that are currently in use. But meeting the two other goals can be really challenging.

All of the teams have done really great work during this conceptual design study. Their results make me excited about how interesting and different the airplanes on the airport ramp could look in 20 years. Another great result of the study is that they have really helped us focus where to invest our research dollars over the next few years, Mark Mangelsdorf, ERA Project chief engineer, said.

Have a look at the stunning aircraft models here:

New Ideas for Greener Aircraft
Three industry teams spent 2011 studying how to meet NASA's goals for making future aircraft burn 50 percent less fuel than aircraft that entered service in 1998, emit 75 percent fewer harmful emissions; and shrink the size of geographic areas affected by objectionable airport noise by 83 percent. NASA
Variation on a Theme
Boeing's advanced vehicle concept centers around the familiar blended wing body design like the X-48. What makes this design different is the placement of its Pratt & Whitney geared turbofan engines on the top of the plane's back end, flanked by two vertical tails to shield people on the ground from engine noise. The design also uses other technologies to reduce noise and drag, and long-span wings to improve fuel efficiency. This design is among those presented to NASA at the end of 2011 by companies that conducted NASA-funded studies into aircraft that could enter service in 2025. NASA/Boeing
Outside the Box, Sort of
Lockheed Martin's advanced vehicle concept proposes a box wing design, which is now feasible thanks to modern lightweight composite (nonmetallic) materials, landing gear technologies and other advancements. Its Rolls Royce Liberty Works Ultra Fan Engine achieves a bypass ratio (flow of air around engine compared to through the engine) nearly five times greater than current engines, pushing the limits of turbofan technology to maximize efficiency. This design is among those presented to NASA at the end of 2011 by companies that conducted NASA-funded studies into aircraft that could enter service in 2025. NASA/Lockheed Martin
Variation on a Theme
Boeing's advanced vehicle concept centers around the familiar blended wing body design like the X-48. What makes this design different is the placement of its Pratt & Whitney geared turbofan engines on the top of the plane's back end, flanked by two vertical tails to shield people on the ground from engine noise. The design also uses other technologies to reduce noise and drag, and long-span wings to improve fuel efficiency. This design is among those presented to NASA at the end of 2011 by companies that conducted NASA-funded studies into aircraft that could enter service in 2025. NASA/Boeing
Another Take on Supersonic
NASA has been exploring a variety of options for quieting the boom, starting with design concepts and moving through wind tunnel tests to flight tests of new technologies. This rendering of a possible future civil supersonic transport shows a vehicle that is shaped to reduce the sonic shockwave signature and also to reduce drag. NASA/Lockheed Martin
AMELIA Climbs High
This computer rendering shows AMELIA (Advanced Model for Extreme Lift and Improved Aeroacoustics), a possible future hybrid wing body-type subsonic vehicle with short takeoff and landing capabilities. Produced through a three-year NASA Research Announcement grant with the California Polytechnic State Institute, AMELIA's ability for steeper ascents and descents could reduce community noise levels on takeoff and landing. A model of this configuration is scheduled for testing in a NASA wind tunnel in the fall of 2011. NASA/Cal Poly
NASALockheed Martin
This artist's concept shows a possible future subsonic aircraft using a boxed- or joined-wing configuration to reduce drag and increase fuel efficiency. This design of an aircraft that could enter service in the 2020 time-frame is one of a number of designs being explored by NASA with teams of researchers from industry and universities. Boxed-Wing Reduces Drag
NASA California California NASA