Some US airlines have begun testing enviromentally friendly fuel. And while the efforts may help the environment, unlike in the European Union, the US government does not force airliners to go green.
The ecological benefits would be undeniable - just one year's avaiation traffic fuelled by bio fuel would equal removing 64,000 cars off the road.
But making the switch can be expensive and there are no long-term plans for companies to use alternative fuel on a regular basis.
Al Jazeera's John Terrett reports from Washington.
