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

With the civil air travel market under increasing pressure from increasing oil rates and environmental legislation, the race is on to find feasible alternatives to traditional kerosene and these up until now seem to come down to numerous types of biofuel.

Not surprisingly, the very first trials of alternative fuel were initiated by British aviation leader, Sir Richard Branson, whose Virgin Atlantic started London to Amsterdam flights with restricted biofuel use in 2008. This was quickly 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 approximately 175 succulent plants, shrubs and trees (some are deciduous, like Jatropha curcas), from the household Euphorbiaceae.

In 2007 Goldman Sachs cited Jatropha curcas as one of the very 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 transferred to research study and advancement into making use of biofuels to power jet airliners. It was reported that Brazilian airline companies Azul, Gol, TAM and Trip would function as tactical consultants for the project.

The current airline company to begin explore new fuels is the Alaska Air Group which has carried out 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 damaging emissions by 10%.

One truly motivating development has been the move away from biofuels which compete head on with food consumers therefore preventing a rate spiral. Not so long back, a surge in use of biofuels in cars triggered a spike in maize prices as US farmers diverted excessive corn to fuel processing.

Hopefully in the future, airline companies and drivers will focus biofuel usage on non-food sources such as jatropha and algae. It would be a mixed blessing undoubtedly if some people ended up starving simply to satisfy another person's green qualifications.