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"To keep the plane from relying on fossil fuels, Air Force One Hybrid's engines use a flexible fuel system. Every day, a special team collects used cooking oil from the White House, the Capitol building and other government-owned commissaries to be cleaned and reused as biofuel. In a pinch, and for areas where biofuels aren't readily available, jet fuel can still be used.
Cooking oil, used to power the four flexible-fuel engines on Air Force One, is taken from the White House and refined to use as aviation biofuel.
Since the job of Air Force One is to help the president make appearances around the world, it has to be ready to fly long distances. A typical 747-400ER can carry around 63,500 gallons of fuel (240,370 L), which is enough to take it from Los Angeles to Melbourne, Australia
. The hybrid version, Blanchard said, is capable of distances at least that long using jet fuel alone. The parallel hybrid system adds another 500 miles (805 km) to that under optimal circumstances.
Col. Branch Heward, of the Presidential Airlift Group stationed at Andrews Air Force Base, Md., said he likes taking the new Air Force One up. "It's as smooth as silk," he said. "But it's strange stepping off the plane and the engines smell like Freedom Fries."
http://science.howstuffworks.com/air-force-one-hybrid1.htm
lots more at link
quite entertaining.