http://www.designfax.net/enews/20100615/feature-3.asp

An MIT-led team has designed a green airplane that is estimated to
use 70% less fuel than current planes while also reducing noise and emission of
nitrogen oxides (NOx).

MIT’s D “double bubble” series design concept is based on a modified
“tube-and-wing” structure that has a very wide fuselage to provide extra lift.
The aircraft would be used for domestic flights to carry 180 passengers in a
coach cabin roomier than that of a Boeing 737-800.

The MIT team also presented NASA with its design for the H “hybrid wing body”
series to replace the 777 class aircraft now used for international flights. The
design features a triangular-shaped hybrid wing body aircraft that blends a
wider fuselage with the wings for improved aerodynamics. The large center body
creates a forward lift that eliminates the need for a tail to balance the
aircraft. The plane is designed to carry 350 passengers. (Images: MIT/Aurora
Flight Sciences)