It's bad enough for some prop airplanes to be referred to as being powered by elastic band. Now the skeptics could begin 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 increasing oil prices and environmental legislation, the race is on to find feasible alternatives to conventional kerosene and these up until now appear to come down to different kinds of biofuel.

Not remarkably, the first trials of alternative fuel were initiated by British air travel leader, Sir Richard Branson, whose Virgin Atlantic started London to Amsterdam flights with limited biofuel usage in 2008. This was 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 thought about too bad for growing mainstream foods items.

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

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

Recently, US aerospace giant Boeing, Brazilian aerial major Embraer and the Sao Paulo state Research Support Foundation moved to perform research study and development into using 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 latest airline to begin explore new fuels is the Alaska Air Group which has conducted internal US flights utilizing a mix of 80 % petroleum based fuel and 20% biofuel made from cooking oil. This mix, it is declared, can cut hazardous emissions by 10%.

One really encouraging development has actually been the relocation away from biofuels which complete head on with food consumers thereby avoiding a cost spiral. Not so long ago, a surge in usage of biofuels in cars triggered a spike in maize prices as US farmers diverted too much corn to fuel processing.

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