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

With the civil aviation market under increasing pressure from rising oil prices and ecological legislation, the race is on to find practical alternatives to standard 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 leader, Sir Richard Branson, whose Virgin Atlantic started London to Amsterdam flights with minimal 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 which can grow in soil thought about too poor for growing mainstream foodstuffs.

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

In 2007 Goldman Sachs cited Jatropha curcas as one of the best candidates for future biodiesel production. It is resistant to dry spell and pests, and produces seeds consisting of 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 making use of biofuels to power jet airliners. It was reported that Brazilian airlines Azul, Gol, TAM and Trip would serve as tactical consultants for the job.

The latest airline to start explore brand-new fuels is the Alaska Air Group which has conducted internal US flights utilizing a mix 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 encouraging development has been the move far from biofuels which contend head on with food consumers thereby preventing a price spiral. Not so long back, a surge in use of biofuels in automobiles caused a spike in maize rates as US 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 blended blessing indeed if some people ended up starving just to please another person's green qualifications.