Some US airlines have begun testing environmentally friendly fuel, despite the fact that unlike in the European Union, the US government does not force airliners to go green.

The ecological benefits of using the fuel are undeniable - just one year's aviation traffic fuelled by biofuel, would equal removing 64,000 cars from the roads.

But making the switch can be expensive and executives say there are no long-term plans for companies to use alternative fuel on a regular basis.

Al Jazeera's John Terrett reports from Washington.

Source: Al Jazeera