Goods sold to passengers on board ships or aircraft are tax free. The passenger can either consume them on board, or import them tax-free into the country they are traveling to, so long as they are within the traveler's duty-free allowance. Most tax regimes also allow travelers entering a country to bring in a certain amount of goods for personal use without paying tax on them, the so-called "duty-free allowance"; because it is not economically justifiable to collect the small amounts of tax involved, and would be an inconvenience to the passengers.