ANZ powers plane on vegetable oil....

[757_Driver]

Alternative propulsion is what we truly need, not alternative fuels.

That may well be the truth - however aircraft, for the moment, have only one viable means of propulsion - with little else on the horizon, whereas road transport and electricity generation both have carbon free alternatives, ready, proven and waiting. So why not concentrate the effort where it will yield the most benefit - rather than banging on about aviation again? Because this is a political, not a scientific argument - thats why.
Unfortunately as long as the environmental argument is hijacked by the dogmatic 'anti' brigade, as it is at the moment then no real progress will ever be made.
Biofuels are a good example of this. In their effort to never be proved wrong 'environmentalists' have pushed a solution that actually increases carbon output as well as pushes staple food prices out of the reach of most of the 3rd world population.
I've still yet to see any reall compelling scientific evidence that says we can alter climate change by reducing carbon output, let alone any evidence that is so compelling that its worth starving millions of people to death over.