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

With the civil aviation market under increasing pressure from rising oil prices and environmental legislation, the race is on to discover viable alternatives to conventional kerosene and these so far seem to boil down to different types of biofuel.

Not surprisingly, the very first trials of alternative fuel were initiated by British aviation pioneer, Sir Richard Branson, whose Virgin Atlantic began London to Amsterdam flights with limited biofuel use in 2008. This was quickly followed by Lufthansa and Air New Zealand who each used different blends of regular fuel and bio derivatives consisting of some from made from jatropha curcas which can grow in soil thought about too bad for growing mainstream foods.

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

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

Recently, US aerospace giant Boeing, Brazilian aeronautical significant 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 Azul, Gol, TAM and Trip would act as tactical consultants for the project.

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

One really motivating advancement has been the relocation far from biofuels which complete head on with food customers therefore preventing a rate spiral. Not so long ago, a rise in use of biofuels in vehicles caused a spike in maize prices as US farmers diverted too much corn to fuel processing.

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