1) replying to the first clip: http://www.youtube.com/watch?v=e8utkoK2DhA

they say "the fuel is nothing more than a salt water"

wrong, they need one more thing - energy to generate EM waves that fires up  that salt waterm and where will they get the enrgy to generate EM waves from ?

2) replying to one comment made above "Basic physics tells you that the amount of energy in the radio waves must be more than the energy created."

it is wrong statement, in physics there is an energy conservation law that says that while changing forms IN A CLOSED SYSTEM TOTAL ENERGY is conserved. in the example it is possible that EM energy wisely unties much more energy of salt water molecules but it has to be tested