Virgin is the first airline in the world to test biodiesel fuel for a London to Amsterdam test flight. This could be groundbreaking.

Although no passengers will be on board, the contents of the plane’s gas tank will have everyone in the airline industry watching. (…)
Airline industry officials, environmentalists and energy companies all have a huge interest in the future of air travel as it pertains to fuel consumption, carbon emissions and global warming.

From the business perspective, the airlines are under great financial pressure because of soaring fuel costs; the price of crude oil is consistently flirting with $100 per barrel. On the environmental side of things, aircraft represent up to 12 percent of greenhouse gas emissions produced by the U.S. transportation sector, according to the Environmental Protection Agency.

Additionally, according to the Federal Aviation Administration, greenhouse gas emissions from domestic aircraft are expected to increase 60 percent by 2025. The Intergovernmental Panel on Climate Change estimates that increases in air transportation over the next 50 years will result in a threefold increase in aircraft CO{-2} emissions and a 13 percent increase in ozone.