The most common fuel is an unleaded/paraffin oil-based fuel classified as Jet A-1 (otherwise known as AVTUR), which is produced to an internationally standardized set of specifications. (see below).

The only other jet fuel that is commonly used in civilian turbine engine-powered aviation is called Jet B, a fuel in the naphtha-kerosene region that is used for its enhanced cold-weather performance. However, Jet B's lighter composition makes it more dangerous to handle, and it is thus restricted only to areas where its cold-weather characteristics are absolutely necessary.
Jet fuel is a mixture of a large number of different hydrocarbons, possibly as many as a thousand or more. The range of their sizes (molecular weights or carbon numbers) is restricted by the requirements for the product, for example, 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; wide-cut or naphtha-type jet fuel (including Jet B), between about 5 and 15 carbon numbers. [1]