It's bad enough for some prop planes to be explained as being powered by rubber bands. Now the skeptics could start having a dig at industrial aircraft flying on everything from cooking oil to melted algae.

With the civil air travel market under increasing pressure from increasing oil rates and ecological legislation, the race is on to discover feasible alternatives to standard kerosene and these so far seem to come down to various types of biofuel.

Not surprisingly, the first trials of alternative fuel were started by British aviation pioneer, Sir Branson, whose Virgin Atlantic began London to Amsterdam flights with minimal biofuel use in 2008. This was rapidly followed by Lufthansa and Air New Zealand who each used different blends of routine fuel and bio derivatives including some from made from jatropha which can grow in soil considered too poor for growing mainstream foods items.

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

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

Recently, US aerospace giant Boeing, Brazilian aeronautical significant Embraer and the Sao Paulo state Research Support Foundation relocated to perform research study and advancement into making use of biofuels to power jet airliners. It was reported that Brazilian airlines Azul, Gol, TAM and Trip would act as tactical specialists for the job.

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

One actually motivating development has been the relocation away from biofuels which compete head on with food customers thereby avoiding a price spiral. Not so long back, a rise in use of biofuels in automobiles triggered a spike in maize prices as US farmers diverted excessive corn to fuel processing.

Hopefully in the future, airlines and motorists will focus biofuel consumption on non-food sources such as jatropha and algae. It would be a mixed blessing indeed if some people wound up starving simply to satisfy another person's green credentials.