Delta Airlines charges a pet fee based on the type of animal and the destination. If you are travelling within the United States, Canada, or Puerto Rico with a small pet, such as a cat or dog that can fit under the seat in front of you, you must pay a one-way fee. However, when planning your trip, keep in mind the additional costs, such as the Delta pet fee. Delta offers cargo services for larger pets that cannot fit under the seat for an additional fee. The cost is determined by your animal’s size and weight, as well as your destination and origin. Therefore, before booking your flight, you should always check with Delta Airlines directly to ensure that your pet can travel safely and to determine the exact Delta pet fee for your specific situation.