Airline-friendly pet carriers are designed to make traveling with your pets aboard airplanes safe and comfortable. Depending upon airline pet policies, pet carriers may be allowed in the cabin of the aircraft as long as they can be stowed under the seat. Airline pet travel must be arranged in advance, as some airlines limit the number of pets aboard any one aircraft. Additional fees may also apply. Some airline-friendly pet carriers are hard-shell and some are soft-sided. Whichever style suits your needs and airline pet policies, be sure to purchase pet carriers that offer plenty of ventilation. Before you and your pet travel, double-check with the airline about pet carrier size and requirements, and restrictions found in airline pet policies.