April 14, 2011:
Eight Swedish Gripen jet fighters, sent to help enforce the Libyan no-fly zone, have been grounded because the base they are operating at, Sigonella in Sicily, is mainly used by American Navy aircraft, and most of the aviation fuel stored there is specially formulated for U.S. military use. The Swedes use commercial jet fuel (Jet A1) for their military aircraft. There is some risk in using American military fuel in warplanes tweaked to use Jet A1, so the Swedish fighters were grounded until the proper fuel could be brought in. With some special conversion equipment, which was not immediately available at Sigonella, you can convert JP-5 to Jet A1.
Militarized jet fuel is unique to U.S. military aircraft. It's more expensive, and two years ago, the U.S. Air Force, in an effort to save some money, decided to allow its transports (C-5, C-17 and C-130) operating in the United States, to use standard airliner fuel, "Jet A", instead of JP-8 military jet fuel.
Jet A and JP-8 are similar, with JP-8 having three additives to make the fuel easier to use in cold weather, and less likely to catch fire when spilled (when fueling or during a crash), less corrosive and so on. These differences make JP-8 a few cents more expensive per gallon. The air force uses about 2.5 billion gallons of fuel a year. In the United States, Jet A is more widely available to military transports (which often operate from commercial air ports) than JP-8, and the military aircraft often use Jet A already with no problems. Jet A1, using a slightly different formula, is used by commercial jets in the rest of the world.
JP-8 is a variation on earlier special formulas, like JP-4 (for Arctic use) and JP-5 (for use on aircraft carriers), and was introduced in the 1970s as a standard military fuel for aircraft, and ground vehicles (not to mention stoves in army field kitchens). JP-8 was used as a substitute for several other fuels in the military, in order to simplify fuel supply. But for jet aircraft worldwide, both military and commercial, Jet A/A1 is the standard.