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

With the civil air travel industry under increasing pressure from rising oil costs and environmental legislation, the race is on to discover feasible alternatives to traditional kerosene and these up until now seem to come down to numerous kinds of biofuel.

Not surprisingly, the very first trials of alternative fuel were started by British air travel pioneer, Sir Richard Branson, whose Virgin Atlantic started London to Amsterdam flights with limited 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 consisting of some from made from jatropha which can grow in soil considered too bad for growing mainstream foodstuffs.

Jatropha is a genus of around 175 succulent plants, shrubs and trees (some are deciduous, like Jatropha curcas), from the household 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 insects, and produces seeds including 27-40% oil.

Recently, US aerospace giant Boeing, Brazilian aerial significant Embraer and the Sao Paulo state Research Support Foundation moved to perform research and advancement into using biofuels to power jet airliners. It was reported that Brazilian airline companies Azul, Gol, TAM and Trip would act as strategic experts for the job.

The most recent airline company to begin experimenting with brand-new fuels is the Alaska Air Group which has performed 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 harmful emissions by 10%.

One really encouraging advancement has been the move away from biofuels which contend head on with food consumers thereby avoiding a cost spiral. Not so long back, a rise in usage of biofuels in automobiles caused a spike in maize costs as US farmers diverted excessive 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 combined true blessing undoubtedly if some people ended up starving simply to please another person's green qualifications.