Based on little more than intuition, my feeling is that within a few years we will see acres, if not square miles, of beautiful modern aircraft parked waiting for a solution. Fiddling around with simulated hydrocarbons will be akin to fitting a gas bag to the roof of a car in WWII.
Huge fortunes, then the dying remnants of fortunes, will be thrown at the problem in a belated last-ditch attempt to continue life as we know it. I suspect that much of such funding will be spent on finding a way to cause the conversion of matter into energy–via a direct coupling with the universe. Science fiction? Well, perhaps, but right now we are seeing the specter of a fuel-less future, while at the some time, a feint image of the holy grail of propulsion.
There is little or no use in achieving a functional and safe source of atomic power in an aircraft, if we have no means of causing it to propel the vessel efficiently; using such advanced energy to continue to squirt us through the turbulent atmosphere would be preposterous.
Right now, research into particle physics shows promise of a new generation of propulsion. But that's all it is, a promise. Dan Brown is jut a tad ahead of his time I'm afraid, but I have no doubt where a good proportion of the GNP of all the major nations should be going...right now.
Life without transport will not just contract back into a warm sepia tinted existence for folk that live in pleasant villages, it will be chaotic...and deadly. If you don't think that's true, you haven't been watching the increasing need for gated, and guarded communities. The fabric of society is creaking already...even while it is still oiled.