With trendsetter celebrities like Paris Hilton and Britney Spears bringing their pint-sized pups along everywhere they go, pet travel has become more and more common. While you don’t need a Louis Vuitton travel crate for your own little Tinkerbell, there are a few things you should keep in mind the next time you decide to fly the friendly skies with a canine (or feline) carry-on.

Most importantly, what kind of pet do you have and how big is he? Most airlines will accept small dogs, cats and domestic birds as carry-on luggage. Your pet will have to fit in an airline approved travel crate, and it must fit under the seat (generally about 10x15x20 inches and weighing less than 40 pounds). He’ll need to be at least eight weeks old, fully weaned and calm. If your pet shows any signs of illness, violence or physical distress airlines won’t allow you to board with him. Most airlines also require your pet’s current health certificates and documentation, so make sure that all shots are up to date.

Once you’ve determined that your pet meets all of your airline’s requirements, its time to make sure he’s comfortable with his newfound jet-setter status. His crate should be large enough for him to lie down comfortably, turn around and stand freely. Trim any long nails so that they don’t snag on the crate door and place a favorite blanket or toy in the crate to make him feel at home. If your little guy is a nervous flyer you’ll need to get him used to his crate before your big trip. Be very careful about using any sort of puppy Prozac, the ASPCA and many veterinarians strongly recommend against using sedatives on pets. In fact, some airlines will not allow your pet to board if they know he has been sedated.

You’ll most likely need to travel domestically with your pet; many countries have strict quarantine requirements for animals arriving internationally. For places such as the Bahamas, you’ll need a special certificate.

Be prepared to pay for your pooch, airlines will charge anywhere from $30 to $90 for the privilege of letting Fluffy or Fido sit under the seat. Also, note that some airlines will consider your pet a part of your carry-on allowance (in most cases each traveler is allowed one carry-on bag and one personal item such as a purse or a briefcase). Once you decide to bring your little buddy along, try to reserve his space as far in advance as possible. Most airlines allow only one kennel in first or business class and two kennels in the main cabin.