It's bad enough for some prop planes to be referred to as being powered by rubber bands. Now the cynics might begin having a dig at industrial aircraft flying on everything from cooking oil to melted algae.

With the civil air travel industry under increasing pressure from increasing oil costs and ecological legislation, the race is on to find viable alternatives to conventional kerosene and these so far appear to come down to different kinds of biofuel.

Not surprisingly, the very first trials of alternative fuel were started by British air travel leader, Sir Richard Branson, whose Virgin Atlantic began London to Amsterdam flights with minimal biofuel usage in 2008. This was quickly followed by Lufthansa and Air New Zealand who each used various blends of routine fuel and bio derivatives consisting of some from made from jatropha which can grow in soil thought about too poor for growing mainstream foods.

Jatropha is a genus of roughly 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 bugs, and produces seeds containing 27-40% oil.

Recently, US aerospace giant Boeing, Brazilian aerial 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 airline companies Azul, Gol, TAM and Trip would function as tactical specialists for the task.

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

One actually motivating development has been the move away from biofuels which complete head on with food customers thereby avoiding a rate spiral. Not so long earlier, a surge in use of biofuels in vehicles caused a spike in maize prices as US farmers diverted too much 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 indeed if some individuals wound up starving just to please another person's green credentials.