I hate to be the nitpicky guy, but it was the Sonic Cruiser that was cancelled, not the Dreamliner. The Dreamliner is better known as the 787, and is kicking Airbus's ass in the marketplace.

Well the problem with the airbus is they spent far too much money developing it and it costs far to much money to buy. On the other hand boeing managed to make a stretched version of thier fuel eff plane and make it more so much cheaper.

The main market for the super airbus is links that are full and can only expand via larger planes.. most of those are in asia.

Passenger and freight airships are the way forward!!
That and globally negotiated incrementally increasing carbon tax.

I rest my case

( and offer no supporting evidence)

Where in the world is Jet A not taxed? In the US it costs nearly $3/gal on average due to the taxes.

When it comes to CO2 emmisions, big ship slow speed diesel engines are great. They are 50% eff. 180g/hp-hr of fuel is normal.
Of course they are the very dirty in Every other way. 17g/kW-h of NOx, 2.5% sulfur in the heavy bunker fuel, on average, making SOx. That is 25,000 parts per million versus 500 parts per million on current US diesel fuel. Max legal is now 45,000 PPM. In northern europe SECA next year it goes down to .5% or 5000ppm.In the fall, ULSD will be below 15 ppm.
Particulate matter is completely unregulated at sea, and in port the use a modified Ringlemann scale to see what percentage of the sky is obscured by smoke.
It is not that ships are getting worse, everyone else is getting better. THe biggest unregulated pollution source in LA right now is the ship engine pollution.

Ironic: Carbon tax, carbon fiber construction to save fuel and thus emmit less GHGs, ie. CO2 and NOX.

Are you guys sure that boats are as super efficient as you think? I know that if you compare an SUV to a powerboat for example, both with a 5.7 liter General Motors engine, the SUV can hold 7-8 people or so and get around 15-18 miles per gallon on the highway. A boat large enough to accomidate 7-8 people doing even 50mph will be lucky to get more than 4 miles per gallon. At low speed it isn't much better since it never gets on plane.

I know for bulky stuff like cars, ships are the cheapest way to transport to most venues, although I've seen aircraft used even for bulk automotive transport, esp of high dollar vehicles like Mercedes, so it certainly exists. I'd imagine that the main advantage of ships is that it's mainly just the weight that matters, not the size, but for aircraft you're very constrained by both weight and size together.

We could always go back to using zeppelins. Maybe a nuclear powered model that wouldn't need frequent refueling?

which is illegal as Jet-A contains lead

Why would that be? It's not as if knocking were a problem for jet engines!

I think you are confusing it with aviation gasoline (used in aircraft piston engines).

The LH2 takes up more volume than kerosene, but not too much more,

Just (!) a factor of more than three, for a given quantity of fuel energy (LHV). This is a huge problem for aircraft design, all the way back to the failed 'Suntan' hydrogen-fueled spyplane effort. The need to keep the hydrogen very cold also severely complicates the design.

Hydrogen is even losing in many rocketry applications, where the importance of high propellant density is not always appreciated (high density ==> lower tank mass, lower pump power). This is especially relevant for first stages.

Paul,
Thanks again for bringing up a very important issue regarding the future of commercial aviation.
I did further look up and made some calculation. Let's take the Boeing 777, the latest Boeing model in production, with an empty operative weight of ~300,000 lbs and a gross takeoff weight of ~600,000 lbs, for ~300,000 lbs of useful load. This aircraft can seat ~400-440 in economical arrangement. Allowing 230-250 lbs per seat including luggage, which is more generous than FAA allowance of 180 lbs per passenger and 30 lbs luggage. So the maximum payload weight is ~100,000 lbs for the passenger version, leaving a remaining 200,000 lbs of useful load for fuel capacity. This should be good for a range of over 4000 nautical mi. Since LH2 weights 3-1/2 times less than kerosene for the same BTU value, expect weight of LH2 of ~60,000 lbs. So, with LH2, the total useful load required, fuel and payload,is now only 160,000 lbs instead of 300,000 lbs as when kerosene is used. This means that the aircraft can be totally redesigned aiming for much lower useful load. Every components can be made lighter and smaller, wings, engines, landing gears, tail empenage, and yes, even the fuselage, because a substantial amount of fuel is carried inside the fuselage as well as inside the wings. With much lighter fuel load, then the fuselage can be made lighter. So, now, we should shoot for a maximum gross weight rating of no more than ~300,000 lbs in order to obtain an useful load of ~150,000 lbs. Of the 150,000 lbs useful load, 100,000 lbs is payload as before. But, since the airplane is now smaller (Wings and Tail empanage) and and weighing half as much, it only requires 1/2 the fuel weight to fly as far, or may be a little more, given the fuselage that still must be of the same size in order to have sufficient space to carry the passenger load. So, instead of requiring 60,000 lbs of LH2 to carry a gross wt. of ~600,000 lbs, we now only need ~35,000 lbs of LH2 to fly a new airplane with a gross wt. of ~300,000 lbs. With fuel of 35,000 lbs of LH2 and 100,000 lbs of payload, we still have ~15,000 lbs of spare useful load capacity, perhaps for carrying extra USPS mail, parcels or other loads. So, even though LH2 requires 3x the volume of kerosene for the same BTU, less LH2 will be required, thus bringing down the increase in volume to 35,000 / 60,000 x 3 = 1.75. The aircraft fuselage can be made slightly taller to accompany the extra volume of fuel. The fuselage weight and drag increase will be quite small.

With smaller engines, fuel load, and airplane weight for a given payload, the cost of flying can be reduced by ~40% if the price of LH2 can be brought down to the same level of kerosene for a given BTU amount. If GE and others can bring down the price of LH2 as promised some day in the future, we will expect airlines and aircraft builders to switch to LH2 as the primary aviation fuel.

Paul,
Very important details you have raised.

When the wing area is reduced by nearly 1/2, the wing volume will be reduce probably to a 1/3 of the previous wing volume, so, you are right, it is not worth it to put LH2 in the wings, especially when thick insulation layer will be needed. But, please realize that jet airliners has relative thin wings, and must store 1/2 or more of its fuel volume in the fuselage. So, before, you have ~80,000 lbs of fuel in the wings, and ~120,000 lbs of fuel in the fuselage. This, plus a heavier fuselage structure capable of holding 220,000 lbs or more of load, aka dead weight. With the newer lighter fuselage designed to handle less load, plus only 135,000 lbs of "dead weight", meaning that your new smaller wing now only have to handle ~1/2 of the bending load of the previous twice-as-large wing. Furthermore, a wing that is only 1/2 as large will have a wing span only 70% that of the larger wing when keeping the same wing aspect ratio. This shorter-span wing will further reduce the bending moment at the wing root, leading to less actual bending load proportionally. A point to consider in structural load design is that as the scale of the structure got larger, then all load-bearing structures if made of the same material must be proportionally thicker to support the weight of the larger structure. That's why dinosaurs and elephants have proportionally much larger bones diameter than smaller animals to support their weight. A larger structure has larger bending moment in addition to mere larger mass, necessitating heavier structure.

Assuming that 1/6th of the fuselage volume of the 777 is for fuel storage, then to double this fuel tank capacity in the new fuselage, its volume only has to be increased by 7/6, and its surface area only has to be increased by 7/6 raised to the 2/3 power = 1.11, or only 11% larger. However, this not accurate, since you want to keep the fuselage's width the same, and only to enlarge its height. So, the increase in surface area may amount to about ~14%. The total wet surface area of the fuselage is well less than 1/2 of the total wet surface area of the whole aircraft, so the increase in fuselage size contributes to but less than 7% of the total skin friction drag of the aircraft. Airliners are designed to cruise at speed nearly the maximum lift/drag ratio (L/D), and at this speed, the skin friction drag made up ~ 2/5 of the total aerodynamic drag, considering that at 0.8 Mach, you are approaching compressibility, hence considerable wave drag occur that would be a lot higher than cruising at 0.6 Mach or lower, while induced drag at maximum L/D speed at 0.8 Mach would grab another 2/5 of total drag. So, 7% x 2/5 = 3%. A measly 3%. I hope you don't think that I took accounting lessons from Andrew Fastow, CFO of Enron. To reduce wave drag, keep the nose section fairly sharp and increase cross-sectional area in front and behind the wing.

"Most airplanes flight are not over long distances, so the fuel fraction of takeoff would be lower" Ah, great, I'm so glad to hear that. Quite true! So, for most of the percentage of the flights, you don't have to worry about LH2 taking up too much of fuel volume, do you? Now that you admit that not that much fuel will be used for shorter flights. But, the reduction of CO2 released will be enormous no matter short or long flights, because frequent takeoff and landing in shorter flights consume a disproportional amount of fuel in comparison to a long flight at high altitudes.

Paul,
In my previous posting, the required increase in fuselage volume to put all the LH2 in fuselage tank (and none in the wings) was miscalculated as ~2x. It should be 2.9x, which can be rounded up to 3x. (1.75 x 120,000/200,000= 2.91) Assuming still that 1/6th of the old fuselage's volume is devoted to fuel storage. Thus, the new fuselage volume now should be 8/6 times the previous volume. I was also previously wrong about postulating to enlarge the fuselage vertical diameter while leaving the horizontal diameter the same. This is because when the fuselage is pressurized at high altitude, fuselage deformation can occur unless the entire cross-sectional area is perfectly circular. To increase the new fuselage volume, it is best to keep the length the same while enlarging the cross-sectional area only, in order to minimize increase in surface area. Thus, the mean cross-sectional area of the new fuselage will be increased proportionately with the new volume of 8/6 times previous volume. And therefore, the surface area of the new fuselage will increase proportionately to the circumference of the mean circular cross-section of the new fuselage, or the square root of 8/6 = 1.15. The new fuselage will have 1.15 times the surface area of the old fuselage, or a 15% increase. Divide this 15% by 1/2 and multiply by 2/5 as discussed in my previous posting will result in = 3%. Still only a meagerly 3% increase in cruise drag even though the new fuselage now has 3x the fuel volume as the old fuselage.