If a pet is likely to be exposed to temperatures less than 45 degrees, the airline also will need a certificate saying that the pet is acclimated to low temperatures. This is also a good time to consult your vet about anything specific you need to know about traveling with your cat or dog. Overall health, behavior, and personality will create the criteria. You know your pet better than anyone, and a good veterinarian will work with you to avoid potential problems along the way. Sedation is not usually recommended, but it depends on the pet.
Some vets advise against it, due to unpredictable side effects at high altitudes.
Others may recommend mild tranquilizers or herbal remedies and flower essences that have a naturally calming effect when the stress of air travel outweighs the risks of sedation. Whatever you use, try it out before the trip. The kennel should be sturdy, clean and large enough for your pet to sit, stand, lie down, and change positions in comfortably. Kennels can contain no more than one adult cat or dog, or a maximum of two puppies or kittens less than 6 months old and 20 pounds each. The kennel door must close securely without locks or other special mechanisms.