some alarmist documentary about peak oil suggested that our grand-kids may never fly in an airplane because their fuel is derived from fossil fuels.
the first commercial flight powered by bio-fuels is planned for next month.
it is only 25% from biological origin, but i'd be surprised if there is any good reason why they couldn't move to 100% bio-fuel in the future.
there will obviously be challenges moving away from fossil fuels, but our planet is fairly large and its resources very poorly managed and grossly underutilized because cheap oil has been distracting us for the last several decades.
certainly, we should expect our wasteful habits to be disrupted, but to suggest that anything which is possible today will become impossible in the future for energy or technology reasons is ridiculous. energy costs may rise, but airplanes will still be flying around 50 years from now.