Transportation fuels refer to liquid or gaseous fuels that are used in vehicles, ships, airplanes and other modes of transportation. These fuels provide energy for propulsion, allowing engines to convert fuel into mechanical work through combustion. The most common types of transportation fuels include gasoline, diesel, jet fuel, and biofuels such as ethanol or biodiesel. They are typically derived from fossil sources like crude oil, but can also be produced from biomass feedstocks or other renewable resources. The choice of transportation fuel depends on the type of vehicle, its efficiency, emissions, and availability in a particular region.