It's hard to find a lot of hard data on either plane, but the 787 has been stated as being 20% more efficient than the 767, and the A380 has been stated as havi

It's hard to find a lot of hard data on either plane, but the 787 has been stated as being 20% more efficient than the 767, and the A380 has been stated as having a per passenger fuel consumption of 81 passenger miles per gallon. So, using the figures I found on wiki [1], it looks like the 787 is fairly considerably, as in using ~75% of the fuel, more efficient than the 787. The A380 may be a big plane, but it's a fairly conventional plane, all things considered. I imagine that if there were a revamp of it with more carbon fiber usage, it could get a lot more interesting. [1] http://en.wikipedia.org/wiki/Fuel_economy_in_aircraft http://en.wikipedia.org/wiki/Fuel_economy_in_aircraft