Here's one to watch. DARPA's BioFuels programme is seen as the strongest candidate to produce an economically viable process for turning biomass into a jet fuel equivalent to everyday JP-8 or Jet-A1, with a net reduction in carbon dioxide production.
DoD pushes to reduce its dependence on oil (USAF photo)
The DoD's research agency is awarding contracts to the likes of Honeywell to commercialise processes to produce bio jet fuel out of everything from canola oil to pond algae. They have 18 months to produce 100litres of biofuel for testing. That doesn't seem like much, but it should be enough to prove the processes are viable.
So will bio jet fuel gallop to aviation's rescue by reducing its contribution to global warming? Maybe, but in Europe alarms are already being sounded over the environmental dangers of large-scale monocultures - vast areas given over to soybean or rapespeed production for biofuels. Producing bio jet fuel sustainably will be as important as producing it economically.