It's bad enough for some propeller planes to be described as being powered by elastic band. Now the cynics could start having a dig at business aircraft flying on whatever from cooking oil to melted algae.

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

Not surprisingly, the very first trials of alternative fuel were started by British air travel leader, Sir Richard Branson, whose Virgin Atlantic started London to Amsterdam flights with biofuel use in 2008. This was rapidly followed by Lufthansa and Air New Zealand who each utilized different blends of routine fuel and bio derivatives including 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 approximately 175 succulent plants, shrubs and trees (some are deciduous, like Jatropha jatropha curcas), from the family Euphorbiaceae.

In 2007 Goldman Sachs pointed out Jatropha curcas as one of the best prospects for future biodiesel production. It is resistant to drought and pests, 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 carry out research study and development into the use of biofuels to power jet airliners. It was reported that Brazilian airline companies Azul, Gol, TAM and Trip would function as tactical experts for the task.

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

One really encouraging development has been the move far from biofuels which complete head on with food customers therefore avoiding a price spiral. Not so long ago, a surge in usage of biofuels in cars caused a spike in maize prices as US farmers diverted excessive corn to fuel processing.

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