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

With the civil air travel market under increasing pressure from rising oil rates and environmental legislation, the race is on to discover feasible alternatives to conventional kerosene and these up until now seem to boil down to various kinds of biofuel.

Not surprisingly, the very first trials of alternative fuel were initiated by British air travel pioneer, Sir Richard Branson, whose Virgin Atlantic started 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 bad for growing mainstream foods.

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

In 2007 Goldman Sachs cited Jatropha curcas as one of the finest candidates 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 transferred to perform research 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 consultants for the task.

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

One actually encouraging development has been the relocation away from biofuels which complete head on with food consumers thus avoiding a cost spiral. Not so long back, a rise in usage of biofuels in cars and trucks triggered a spike in maize prices as US farmers diverted excessive corn to fuel processing.

Hopefully in the future, airline companies and motorists will focus biofuel consumption on non-food sources such as jatropha and algae. It would be a combined blessing certainly if some people ended up starving just to somebody else's green qualifications.