The world's largest aircraft manufacturer says biofuel-powered aircraft will flying the friendly skies as early as 2011, a timeline far more accelerated than many thought.

Darrin Morgan, who oversees strategy development and execution for Boeing's Sustainable Biofuels Program, tells Wired.com the company expects authorities to certify a biofuel-fuel blend jet fuel for commercial use in the near future. It's a remarkable prediction, because aircraft manufacturers, the U.S. Air Force and airlines – desperate to find an alternative to fossil fuels so they might save money, not necessarily change their notoriously polluting ways – have only started experimenting with alt fuels.

"We think it's going to happen in three to five years," Morgan says of the certification process. "Faster than most people thought."

The beauty of biofuels from an aviation standpoint is they require no modification to the aircraft - they're a direct replacement for kerosene. But harvesting enough biomass to meet the industry's need remains a huge barrier to widespread adoption of the alternative fuel.

The airline industry burns about 85 billion gallons of kerosene annually. The Guardian says fueling the world's 13,000 commercial airplanes with nothing but, say, soybean-based fuel, would require using the equivalent of the entire land mass of Europe to grow soybeans. Boeing expects airlines to use a 30 percent blend of biofuel.

The drawbacks of crop-based biofuels is one reason Boeing is pursuing algal fuels, and indeed California startup Solazyme has developed an algal jet fuel that behaves just like kerosene. Morgan says algal fuels hold great promises, but it is a family of fuels called synthetic paraffinic kerosene – which includes those distilled from the oils of Helianthus (sunflowers) and jatropha – that are closest to becoming certified.

Morgan bases his confidence on the fact synthetic paraffinics have a similar composition to coal-to-liquid fuels already approved for aviation use. "It's dirty, but it's certified," Morgan says of liquid coal.

"If you fly in or out of

South Africa, you're probably using it."

South Africa is home of

Sasol, the company that pioneered coal to liquid technology. Morgan notes that, compared to liquid coal, bio-derived synthetic paraffins can significantly reduce lifecycle greenhouse gas emissions. They're also a direct replacement for kerosene, meaning no modifications to the aircraft are needed. "It's simple chemistry,"

Morgan says. "If molecules in a biofuel are like those in already approved drop-in synthetic kerosene from coal, then by definition it's a drop-in fuel."

The airline industry seems to be getting on board, in no small part because they're being hammered by fuel prices, and several of the largest carriers are experimenting with biofuel. Boeing has joined Air New Zealand and Virgin Atlantic, Airbus has teamed up with Honeywell and JetBlue and British Airways is working with Rolls Royce. Even the U.S. Air Force is looking for alternatives to kerosene. But given the tumble in oil prices and the cost of developing alternatives, one has to wonder how serious their commitment will be.

It's also an open question whether biofuels are any better than fossil fuels. Environmentalists derided Virgin Atlantic's much-ballyhooed biofuel test flight as a "nonsensical" publicity stunt. Environmentalists like Friends of the Earth argue airlines should limit flights before embracing biofuels because there are "real doubts" as to the sustainability and environmental benefits of biofuels.

POST UPDATED 10:50 a.m. and 2:25 p.m. PST.

Photo by Boeing.