Early piston-powered aircraft used the same fuels as your car -- gasoline and diesel. But the development of jet engines necessitated a different kind of fuel. Although a few wacky wingmen advocated the use of peanut butter or whiskey, the aviation industry quickly settled on kerosene as the best fuel for high-powered jets. Kerosene is a component of crude oil, obtained when petroleum is distilled, or separated, into its constituent elements.
If you have a kerosene heater or lamp, then you might be familiar with the straw-colored fuel. Commercial aircraft, however, demand a higher grade of kerosene than fuel used for domestic purposes. Jet fuels must burn cleanly, yet they must have a higher flash point than automobile fuels to reduce the fire risk. Jet fuels must also remain fluid in the cold air of the upper atmosphere. The refining process eliminates all suspended water, which could turn into ice particles and block fuel lines. And the freezing point of the kerosene itself is carefully controlled. Most jet fuels won't freeze until the thermometer reaches minus 58 degrees Fahrenheit (minus 50 degrees Celsius).