Just because you can take your pet on a plane doesn't mean you should; often, the stress of traveling is as bad as or worse on your pet than being separated from you. But if you're making a long-term move or a long trip and simply can't bear to be separated, most airlines offer provisions for taking your pet along – as long as you follow a few basic rules and have the right sort of carrier. Each airline imposes its own regulations about pets traveling by air, although most of the requirements for pet carriers echo guidelines set by the International Air Transport Association.

Ways Your Pet Can Travel

Ultimately, there are three ways your pet can take to the air. Small dogs and cats (and at the airline's discretion, other small pets) may be allowed in an in-cabin carrier, as long as it's small enough to stow under the seat in front of you. Larger pets and animals that your airline won't allow in the cabin – which usually includes amphibians and reptiles – can be shipped as cargo or as checked baggage.

Warning

Airlines either strictly limit the transport of brachycephalic (snub-nosed) cats and dogs as checked baggage or won't allow them at all. Always check with your airline for their specific requirements. Snub-nosed cat breeds include Burmese, Persian, Himalayan and other exotic short-hair cats; and a number of dog breeds, including pugs, pit bulls, Pekingese and all mastiff breeds. A few airlines, like Southwest, simply won't accept animals as checked baggage at all.

Pet Carrier Size

No matter where your pet is going – in the cargo hold, in the checked baggage hold or under the seat in front of you – the carrier must be large enough for Fido or Fluffy to comfortable sit or stand erect, without his head touching the top of the carrier. Your pet also needs to be able to turn around and lie down – i.e., stretch out – comfortably, without any part of her body protruding from the crate. Pet carriers large enough to accommodate very big dogs may be subject to oversize or overweight handling fees.

Choosing an In-Cabin Pet Carrier

Choosing an in-cabin pet carrier boils down to common sense: The carrier should be leak-proof and well-ventilated, and it may have either hard or soft sides. Some airlines will issue maximum dimensions for in-cabin carriers – for example, on Southwest, they can be no larger than 18.5 inches long by 8.5 inches high and 13.5 inches wide – but the bottom line is that the carrier must fit completely under the seat in front of you so it doesn't impede access to the aisle. Bear in mind that, excepting appropriate potty breaks at the airport, your pet will have to stay in the carrier for its entire trip, and most airlines count the in-cabin carrier as part of your carry-on luggage allowance.

Tip

Under-seat storage space can vary a surprising amount, even on the same airline. For example, the middle seat often has a wider storage area than the aisle or window seat. When in doubt, call your airline or use a third-party service like Seat Guru to find the dimensions of the under-seat storage for a specific seat.

Cargo and "Checked Bag" Carriers

Again, the airline is the ultimate arbiter of which carriers are acceptable for pets flying as cargo or checked bags – if they accept pets in the cargo or luggage areas at all. But, as a bare minimum, the carrier must satisfy all the following requirements:

  • The sizing requirements described (room to sit, stand erect, turn around and lie down comfortably).
  • Hard-sided construction made of rigid plastic, metal or wood, with a solid roof. (Note: Some international airlines will not accept carriers made of wood).
  • Ventilation openings on three or four sides, depending on the flight and/or animal breed.
  • Working handles on the outside of the crate. If the crate has wheels, they must be either removable or lockable.
  • Proper labeling, which includes the letters "Live Animal" in 1-inch letters on the crate's top and at least one side, plus arrows to indicate which side is up.
  • A metal door that closes securely but doesn't have to be locked to stay that way, so airline staff can open it in case of an emergency.
  • The crate must include some sort of bedding to absorb "accidents."
  • Your pet must have access to food and water dishes affixed to the inside of the door; airline staff should be able to access the dishes without opening the door.
  • Shipper/owner contact information should go on top of the kennel, along with the pet's name and, if applicable, feeding instructions and a supply of dry food. 

Some of the items that airlines may specifically prohibit, at their discretion, include top-opening kennels, kennels with plastic doors or latches, collapsible kennels, and kennels made entirely of wire. Again, the key is to check with your airline well in advance of your flight so you can make sure you've secured an adequate kennel.

Tip

How does your pet feel about its new kennel? Give Fido plenty of time – preferably a couple of weeks – to get used to it and form positive associations with it before he has to endure the stress of traveling. If your pet's comfort isn't motivation enough, remember that airlines may refuse to carry your pet if he shows aggressive behavior or is otherwise "disruptive," all of which can be motivated by fear.

Other Restrictions to Watch For

Airlines may impose a few more restrictions on where Fido can and can't go, including no pets as checked luggage on certain Airbus aircraft, no pets in some first-class or business-class cabins, and no pets on flights longer than 12 hours. But, as a general rule, if you approach the airline representatives as part of the solution instead of part of the problem, they'll help you and your pet find a way to get from here to there.