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

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

Not surprisingly, the first trials of alternative fuel were started by British aviation pioneer, Sir Richard Branson, whose Virgin Atlantic started London to Amsterdam flights with restricted biofuel usage in 2008. This was rapidly followed by Lufthansa and Air New Zealand who each utilized various blends of regular fuel and bio derivatives consisting of some from made from which can grow in soil considered too poor for growing mainstream foods.

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 mentioned Jatropha curcas as one of the very best candidates for future biodiesel production. It is resistant to drought and pests, and produces seeds containing 27-40% oil.

Recently, US aerospace giant Boeing, Brazilian aeronautical major Embraer and the Sao Paulo state Research Support Foundation moved to perform research and development into using biofuels to power jet airliners. It was reported that Brazilian airlines Azul, Gol, TAM and Trip would serve as strategic consultants for the project.

The most recent airline company to start try out new fuels is the Alaska Air Group which has actually performed internal US flights utilizing a mix of 80 % petroleum based fuel and 20% biofuel made from cooking oil. This mixture, it is claimed, can cut harmful emissions by 10%.

One really motivating development has actually been the move far from biofuels which contend head on with food customers thus avoiding a cost spiral. Not so long earlier, a rise in use of biofuels in automobiles triggered a spike in maize prices as US farmers diverted excessive corn to fuel processing.

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