While millions of Americans are vacationing this summer, many of their four-legged friends will be left behind with pet-sitters or put in a kennel. But depending on where they’re vacationing, there’s a good chance Fido can join in the family fun.

Travelers often say they feel guilty about leaving pets — considered part of the family by many — behind while on vacation. A 2001 survey by the American Veterinary Medical Association showed that 58.3 percent of households in the U.S. own at least one pet, and of these households, 46.9 percent say their pets are members of the family.

Traveling with pets isn’t as difficult as one might think. Almost half of U.S. hotels allow guests to bring pets with them, according to a survey conducted by the American Hotel & Lodging Association in 2006. Bringing pets along on vacation can be a great experience, but doing so requires planning and preparation.

AAA, which publishes “Traveling With Your Pet: The AAA PetBook,” added over 1,000 new pet-friendly lodgings to its latest edition of the book, bringing the total to 13,000 locations. And those are just the AAA-rated ones; there are plenty more out there, including those listed on Web sites such as tripswithpets.com, petswelcome.com and dogfriendly.com.

When looking for a place to stay (with your pet), you may want to consider the fees and/or pet deposits, which vary between hotels, sometimes even within the same chain. The Ritz Carlton, for example, which only allows pets in certain locations, charges $150 per pet in its New Orleans hotel, while the cost at the Cleveland location is only $50. The Best Western also said that the pet fees among its “1,900 pet-friendly hotels” vary.

Loews Hotels allow pets at all U.S. locations. According to the company's Web site, they charge a $25 fee, but as part of their “Loews Loves Pets” program, all pets are given their own bowl and a treat during their stay. All Westin Hotels also allow dogs, but require a $100 deposit and a signed damage waiver.

Traveling the Friendly Skies With Man's Best Friend

So now you’ve booked a hotel, but how do you get there with your pet?

For those who are flying to their vacation destinations, there’s even more to consider when traveling with pets. Taking a look at a sampling of popular airlines, most do allow pets, but not without restrictions and charges.

You have two options for flying with pets. You can take your pet as a carry-on item or have it placed in the cargo compartment with luggage.

American Airlines charges $80 for pets to be brought on board and counted as a personal item or carry-on bag. Your furry friend can also be checked as baggage and kept in the cargo bay for $100. Delta offers the same services, but charges only $50 for the pet to be brought in the cabin.

US Airways and JetBlue both prohibit transporting pets in the cargo bay because of unsafe temperatures and air pressure fluctuations in that compartment. However, they do allow pets on-board for a charge of $80 and $50, respectively, each way.

Not all pets are treated equally by airlines. While Delta allows birds, ferrets, rabbits, hamsters and guinea pigs on-board, JetBlue and American allow only cats and dogs. Check with the carrier on their specific pet policy before booking your flight.

Just What the Pet Doctor Orders

With all this traveling business, let's not forget health and safety issues. The American Veterinary Medical Association has some advice for traveling with animals.

First, it’s important to consider the comfort of your pets while on the plane and in the hotel.

Some animals feel uncomfortable in an unfamiliar environment. In addition, some animals may not be healthy enough for such types of travel. If you’re unsure about whether your pet is in suitable health for the trip, the AVMA recommends talking to your veterinarian beforehand.

Even for healthy animals, you should get in touch with your vet ten days ahead of time to make sure your pet has up-to-date vaccinations, which may be required for travel.

Regarding air travel with pets, the AVMA says to make sure transport crates are the appropriate size. These crates, which can be purchased at pet shops or from the airline, should be big enough to let your pet stand up completely and turn around during the flight.

The bottom of the crate needs to be leak-proof and you should cover it with absorbent material. They also need to be well-ventilated and labeled “Live Animals,” with an arrow showing the upright position.

For the pet’s comfort, the AVMA advises that you have him or her travel with an almost-empty stomach. Contrary to popular belief, it is not recommended for pets to be given tranquilizers when traveling by air, according to AVMA.

AAA's guidelines say don't forget to brush your pet up on its good behavior before leaving.

“Unfamiliar travel situations may test the temperament of even the most well behaved pet,” the motor group said in a statement on its Web site.