First it was the personal TVs with multiple channels on each seatback. Then it was the comfy seats. Now, Virgin Atlantic Airways hopes to revolutionize air travel once again.

On Sunday, the British airline owned by billionaire Richard Branson tested a new biofuel made from babassu nuts and coconut oil on a flight from London to Amsterdam. The 747's fuel supply was about 25% biofuel, with the rest coming from traditional kerosene gas. Branson says he looked into many different sources of biofuel, and landed on the babassu/coconut combination because it's more environmentally sound than many other sources that would require massive amounts of farm land.

But some criticize Branson, who once signed Janet Jackson and the Rolling Stones, for using this as just another publicity stunt. Jos Dings, director of the European Federation of Transport and the Environment, told ABC News that calling something a "biofuel" does not necessarily mean it is environmentally friendly.

"It depends crucially on what sort of biofuel you use, how much land that biofuel actually uses," Dings said. "If Virgin would power its entire fleet with biofuel, it would have to use about half of the UK's arable land."

In September, Branson pledged to invest $3 billion over the next 10 years to the Clinton Global Initiative to help create sustainable fuels for airplanes, trains, and automobiles. Also last fall, Branson partnered with Al Gore to establish the Virgin Earth Challenge, a $25 million award for the development of technology that can suck greenhouse gases from the atmosphere for 10 consecutive years and "contribute materially to the stability of Earth's climate."

In January, the political magazine Mother Jones reported that Branson is also considering a host of non-traditional, non-first-generation biofuels such as corn, soy, and palm oil, all of which do require vast amounts of land to raise and deplete the world's food and fresh water resources. Instead, he wants to create a fuel system that would be adaptable to diverse, region-specific fuel sources. Deron Lovaas, director of the Move America Beyond Oil Campaign at the Natural Resources Defense Council, an environmental watchdog group, told Mother Jones it wouldn't be unreasonable, even, to imagine a fuel derived from algae.

With more than $3 billion on the table and all eyes on Branson, it's hard to imagine this is merely for publicity. We'll see what happens over the next 10 years.