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

With the civil aviation industry under increasing pressure from rising oil rates and environmental legislation, the race is on to discover practical options to traditional kerosene and these up until now seem to come down to different types of biofuel.

Not surprisingly, the first trials of alternative fuel were started by British air travel leader, Sir Richard Branson, whose Virgin Atlantic began London to Amsterdam flights with minimal biofuel usage in 2008. This was rapidly followed by Lufthansa and Air New Zealand who each utilized different blends of and bio derivatives consisting of 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 family Euphorbiaceae.

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

Recently, US aerospace giant Boeing, Brazilian aerial major Embraer and the Sao Paulo state Research Support Foundation relocated to perform research and development into the usage of biofuels to power jet airliners. It was reported that Brazilian airlines Azul, Gol, TAM and Trip would function as strategic experts for the job.

The newest airline company to begin explore 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 mixture, it is claimed, can cut hazardous emissions by 10%.

One really encouraging advancement has been the relocation away from biofuels which compete head on with food consumers therefore preventing a cost spiral. Not so long ago, a surge in use of biofuels in cars caused a spike in maize rates as US farmers diverted excessive corn to fuel processing.

Hopefully in the future, airline companies and drivers will focus biofuel intake on non-food sources such as jatropha and algae. It would be a combined blessing indeed if some individuals ended up starving just to please another person's green credentials.