posted on Dec, 8 2006 @ 07:17 PM
Well the 787 (code Y2) is the replacement for the 767 and possibly the 777-200ER.
It has a carbon composite fuselage, bleedless engine and promises up to 20% fuel efficiency compared to an A330.
Boeing 787 site
The 797 doesn't exist. It's rumoured that it will be the plane under the codename Y1 aka the 738 replacement. Boeing has stated that they need a new
engine in order to make a truly new plane that offers real advantages over the 737NG /(700-800-900 models). Expert guessed that by 2012-13 the plane
will be announced.
There's is a third plane codename Y3 which will be the replacement for the 777 and 747. It is rumoured to de launched by 2015.
In you are referring the the blended wing plane as the 797, that is only a myth. The project doesn't exist. Boeing is studying the BWB concept but
not for commercial purposes.
Check out Boeing's sales VP for info on it