Different aircraft engines use different fuels; the most common types are Jet A or A-1 for jet and turboprop engines, and avgas for piston engines.
Different types of aircraft engine use different types of fuel.
Turboprops and jets burn jet-fuel. The most common jet fuel is Jet A-1, which is a type of kerosene (in the U.S., Jet A, which has a slightly higher freezing point but is otherwise very similar to Jet A-1, is used instead); in very cold climates, Jet B, a 70-30 mixture of gasoline and kerosene, is used, as it has a lower freezing point than Jet A or A-1. Some airlines have tested biofuels as an alternative to traditional hydrocarbons.
Piston-engine aircraft most commonly use avgas - typically 100LL, which is essentially 100 octane leaded gasoline. Because of the relatively high cost of avgas, it's possible to find piston engines that have been built or adapted to use other fuels such as Jet A/A-1, mogas (motor gasoline, i.e. normal gasoline like that used for road vehicles) or diesel.
fuel-tanks are located differently on different aircraft but they are very commonly placed in the wings.
This tag is suitable for questions about all fuel types, as well as questions about procedures and regulations related to fuel. Questions about calculating fuel requirements or optimizing fuel use should usually be tagged performance and/or flight-planning as well. Questions about fuel economy should use fuel-consumption instead.