Syntroleum Fischer-Tropsch Jet Fuel Used in Successful B-52 Eight Engine Flight Test.

TULSA, Okla. -- Syntroleum Corporation (Nasdaq:SYNM) a leader in Fischer-Tropsch (FT) technology, announced today that a B-52 Stratofortress Bomber aircraft completed a successful flight test mission using a blend of Syntroleum's ultra-clean jet fuel and traditional JP-8 in all eight engines. The flight test, performed on December 15, 2006 at Edwards Air Force Base, Calif., marks the first time a B-52 has flown using a synfuel blend as the only fuel on board. The Air Force first flight tested a 50/50 blend of Syntroleum fuel and conventional JP-8 on September 19, 2006, utilizing the fuel in two of the B-52's eight engines.

"This historic flight using a blend of Syntroleum's fuel in all eight engines of the B-52 once again demonstrates that our fuel can meet the stringent requirements of the DOD as the Air Force continues the process of testing and certifying a synthetic fuel blend for its aviation fleet," said Jack Holmes, president and CEO of Syntroleum. "We continue to believe that the performance of our FT fuels further validates the quality and integrity of our product, while the successful completion of this test provides Syntroleum with an opportunity for additional long-term contracts with the military."

To learn more about the DOD's Assured Fuels Initiative program and the Air Force's flight test, please see the following links: www.syntroleum.com, www.af.mil/news/story.asp?storyID=123035568.

About Syntroleum (Nasdaq:SYNM)

Syntroleum Corporation owns a proprietary process for converting natural gas or synthesis gas derived from coal and other carbon-based feedstock into synthetic liquid hydrocarbons. The company plans to use its technology to develop and participate in natural gas and coal monetization projects in a number of global locations.

This document includes forward-looking statements as well as historical information. Forward-looking statements include, but are not limited to, economics and development of possible Fischer-Tropsch projects, future capital and operating costs of the company, quality and performance of Fischer-Tropsch catalysts, potential results for Syntroleum shareholders, testing, qualities and uses of Fischer-Tropsch fuels, future programs with the United States government or it various entities, ownership of intellectual property rights, execution of definitive agreements, technology development and market development. When used in this document, the words "anticipate," "believe," "estimate," "expect," "intent," "may," "project," "plan" "should," and similar expressions are intended to be among the statements that identify forward-looking statements. Although Syntroleum believes that its expectations reflected in these forward-looking statements are reasonable, such statements involve risks and uncertainties and no assurance can be given that actual results will be consistent with these forward-looking statements. Important factors that could cause actual results to differ from these forward-looking statements include failure to execute definitive agreements, the potential that commercial-scale GTL or coal-to-liquids plants will not achieve the same results as those demonstrated on a laboratory or pilot basis or that such plants will experience technological and mechanical problems, the potential that improvements to the Syntroleum Process currently under development may not be successful, the impact on plant economics of operating conditions (including energy prices and government support for such plants), construction risks, risks associated with investments and operations of GTL and coal-to-liquids plants, the ability to implement corporate strategies, competition, intellectual property risks, Syntroleum's ability to obtain financing and other risks described in the company's filings with the Securities and Exchange Commission.

[R] "Syntroleum" is registered as a trademark and service mark in the U.S. Patent and Trademark Office