Jet fuel is a type of 
aviation fuel designed for use in 
aircraft powered by 
gas-turbine engines. It is clear to straw-colored in appearance. The most commonly used fuels for commercial aviation are Jet A and Jet A-1 which are produced to a standardized international specification. The only other jet fuel commonly used in civilian turbine-engine powered aviation is Jet B which is used for its enhanced cold-weather performance.
Jet fuel is a mixture of a large number of different hydrocarbons. The range of their sizes (molecular weights or carbon numbers) is restricted by the requirements for the product, for example, the freezing point or smoke point. 
Kerosene-type jet fuel (including Jet A and Jet A-1) has a 
carbon number distribution between about 8 and 16 carbon numbers (carbon atoms per molecule); wide-cut or 
naphtha-type jet fuel (including Jet B), between about 5 and 15 carbon numbers.