For years DaimlerChrysler Aerospace Airbus corporation has been funding a R&D project called Cryoplane. This aircraft uses liquid hydrogen to power twin turbofan engines. So far it has been
successful in flight tests although it is not yet cost-competitive with current Airbus vehicles that burn fossil fuels. The main drawback is the need for cryogenic tanks to store the liquid/slush
hydrogen, whose shapes are restricted to spherical, or short cylindrical, tanks to prevent excessive heating and boil-off of the hydrogen. This means that the fuel cannot be stored in the wings. The bulky hydrogen tanks must be located either inside the fuselage or hang underneith the wings. Either case subtracts cargo capacity or aerodynamic efficiency which directly affect the performance and cost-competitiveness of the aircraft. Liquid hydrogen is also flammable, just like fossil fuel.

Reference: Flug Revue
Flug Revue

The key to overcoming this obstacle is a new storage system for the hydrogen. The ideal would negate the need for cryogenic tanks and allow fuel to be stored in the wings. I now introduce liquid sodium borohydride. This awesome storage medium for hydrogen has been demonstrated by Millennium Cell. It is a liquid at room temperature and pressure, stores 66 percent as much hydrogen per litre as liquid hydrogen, has the same mass-density as water, can be pumped into and out of a tank, and can be re-charged with hydrogen over and over again. The spent fuel is composed of borax in water, and the water can be evaporated away leaving a powder similar to laundry detergent. This means the aircraft does not have to carry spent fuel as excess weight.

Reference: Millennium Cell
Millennium Cell

Now here is the interesting part. The fuel is not flammable, except in the presence of a rare-earth catalyst. If large aircraft were to use this fuel instead of kerosene they would no longer be effective weapons against us. They would no longer be flying bombs. And attacks like the one on Sept.11,2001 would not be nearly as devastating.