On the commercial transportation, mostly with airlines, the baggage allowance is the amount of checked or carry-on luggage the airline will allow per passenger. On some airlines, this is the amount that is allowed free of charge. In other cases, this is the firm limit, and carrying additional weight for an extra payment is not an option.

The general allowance per passenger depends on the policies of the particular airline. On U.S. domestic flights, it was typical for an airline to allow passengers to check up to 2 pieces of lugagge that are up to 50 pounds (22.7 kg) each free of charge (total 100 pounds = 45.4 kg), and this can be exceeded for a fee. This changed during 2007 with most airlines now charging for both the first and second bag. However, within Europe, and often on flights between the United States and Europe, the limit is as low as 40 pounds (18 kilograms) total per passenger, and many airlines do not allow passengers to exceed this amount, even with payment of a fee. Many passengers complain about this limit, because after the typical 15-20 pounds (7–8 kg) of the suitcase itself, little room remains for any other items.