A 411th Flight Test Squadron F-22A Raptor takes on fuel in-flight from a KC-135R on August 19, 2008. What is unusual is that the fuel being transferred was a 50/50 mix of normal and synthetic composition.

A USAF C-17A Globemaster III over New York City towards the end of the first transcontinental flight using synthetic fuel. The airlifter had departed from McChord AFB in Washington State to McGuire AFB in New Jersey

Boeing's B-52 Stratofortress was ideal for testing alternative fuels as it had eight engines. A Stratofortress is shown on its take off run al Edwards AFB on December 15, 2006 - this was the first time all of the type’s engines had used a blend of synthetic fuel and JP-8.

This Airbus A380 is pictured during the three-hour test flight that took place on February 1 this year using 60% Jet A-1 and 40% Shell GTL (a gas to liquid fuel). The blend performed identically to conventional Jet A-1.

<...> time a USAF aircraft had broken the sound barrier using this mix of fuel.

A publicity photo of Sir Richard Branson and Captain Geoff Andreasen of Virgin Atlantic taken before the flight from London to Amsterdam on February 24, 2008 this year, which used a renewable fuel. Behind them is one of the Boeing 747-400s four General Electric CF6-80C2BF5 engines which used a biofuel made from coconut oil and babassu oil. The airline was the first in the world to use renewable fuel.