It's bad enough for some propeller planes to be referred to as being powered by elastic band. Now the skeptics might start having a dig at commercial aircraft flying on whatever from cooking oil to liquefied algae.

With the civil air travel industry under increasing pressure from rising oil rates and environmental legislation, the race is on to find viable options to conventional kerosene and these so far seem to come down to numerous types of biofuel.

Not remarkably, the very first trials of alternative fuel were by British aviation leader, Sir Richard Branson, whose Virgin Atlantic started London to Amsterdam flights with restricted biofuel use in 2008. This was rapidly followed by Lufthansa and Air New Zealand who each used various blends of regular fuel and bio derivatives including some from made from jatropha which can grow in soil thought about too poor for growing mainstream foods items.

jatropha curcas is a genus of approximately 175 succulent plants, shrubs and trees (some are deciduous, like Jatropha jatropha curcas), from the family Euphorbiaceae.

In 2007 Goldman Sachs cited Jatropha curcas as one of the very best prospects for future biodiesel production. It is resistant to dry spell and pests, and produces seeds containing 27-40% oil.

Recently, US aerospace giant Boeing, Brazilian aeronautical major Embraer and the Sao Paulo state Research Support Foundation moved to perform research and advancement into making use of biofuels to power jet airliners. It was reported that Brazilian airline companies Azul, Gol, TAM and Trip would serve as strategic consultants for the project.

The current airline to start experimenting with new fuels is the Alaska Air Group which has performed internal US flights using a blend of 80 % petroleum based fuel and 20% biofuel made from cooking oil. This mix, it is claimed, can cut damaging emissions by 10%.

One really motivating development has been the relocation away from biofuels which complete head on with food customers thus preventing a price spiral. Not so long ago, a rise in use of biofuels in vehicles triggered a spike in maize costs as US farmers diverted excessive corn to fuel processing.

Hopefully in the future, airlines and motorists will focus biofuel usage on non-food sources such as jatropha curcas and algae. It would be a mixed blessing indeed if some individuals wound up starving simply to please somebody else's green credentials.