According to the text: 

    The choice to take your dog in the cabin with you versus traveling in the cargo hold will often be decided for you by the size of the animal and the airline’s policy. Some airlines restrict the total number of pets allowed on any given flight, and these spots are usually parceled out on a first-come, first-served basis—so you will want to book early.

    Expect to pay a fee to fly with your dog. Current standard fees range from around $75 to $200 each way, and can go up to several hundred dollars for larger dogs that must be transported on cargo planes.

    If at all possible, choose a direct flight. As tough as flying is on a dog, especially in the cargo hold, submitting them to even longer travel times plus multiple encounters with baggage handling can easily go sideways. My family flew cross-country with our dog several years ago, and had purchased direct flights, but due to aircraft problems on the way home had to switch to a connecting itinerary. During our connection in St. Louis, we watched helplessly through the airport windows as a baggage hander in St. Louis let our dog’s travel crate nearly free-fall onto the tarmac. When we ____________ at our home airport, the crate was shattered and the dog significantly traumatized.