Southwest Airlines makes it easy to travel with small pets like cats or dogs. Their carry-on pet policy allows you to bring your pet in the cabin if it's in a soft, well-ventilated carrier that fits under the seat. Your pet has to stay in the carrier the whole time, and the carrier takes the place of your carry-on bag. Make sure to book your pet’s spot early because space is limited. The Southwest Airlines carry on pet policy helps keep things safe and comfortable for both passengers and pets.