One that I like:
Reaction Engines Limited :: LAPCAT A2 Facts and Figures
I recalculated the use of energy per seat per kilometre. Its high, its about 17 MJ.
Current jet airplanes have this figure somewhere around 1 - 1.5
Using about the same calculations, my car which uses 5l/100km gets 2MJ figure if I drive alone.
Jets vs pistons
Jets go at very high altitudes at high speeds (0.8 mach+) and are about as efficient as piston/propeller planes which go at lower attitudes at lower speeds(0.5 mach). By efficient I mean that they have about the same consumption per seat per kilometre. So which would you choose if you want to get somewhere?
I think that air-travel will stay course someone will always want to get somewhere very quickly. Although various maglev trains are possible, just to build a track for it requires massive amounts of of energy and materials.
