What happens when the great pandemic pet boom meets the post-vaccination travel boom? This holiday season, industry experts anticipate a new wave of animal owners will hit the road with the dogs, cats and other creatures they acquired during months of isolation.

Rental service Vrbo told The Washington Post demand for pet-friendly vacation homes rose 40 percent from last year. Pet travel site BringFido said its hotel bookings during spring this year far outpaced pre-pandemic times, and it saw vacation rental bookings increase more than 100 percent.

“All of the indicators suggest that with the pandemic puppies and whatnot, that the phenomenon is real and that people are traveling with their dogs even more than before the pandemic,” said Jason Halliburton, BringFido’s chief operating officer.

A “pet-friendly” option on Hilton’s booking website has been its third-most-selected filter, according to Bill Duncan, global category head for focused service and all-suites brands. The company is responding to meet that demand. By Jan. 1, Homewood Suites will join Home2 Suites as brands that accept pets at 100 percent of properties in the United States and Canada. By the end of the first quarter of 2022, brands including Hilton Garden Inn, Hampton by Hilton and Tru by Hilton will also be universally pet-friendly.

Due to the rise of vacation rental companies, there are more pet-friendly lodging options than ever. But traveling with pets, especially by air, has gotten significantly more complicated. Here’s what experts say people should know about hitting the road — or air, or rails — with pets.

Flying with pets is trickier now

People who last flew with their pets before the pandemic face a whole new set of rules. The easy days of flying with an emotional support animal free are gone. Since the beginning of this year, only trained service dogs have been allowed to fly in the cabin at no extra charge. That is because of new federal rules, which were in the works before the pandemic, that enabled airlines to crack down on pet-toting passengers.

Now, travelers who want to fly with their small pets — typically cats and dogs, though some airlines are more flexible — must pay a fee and put animals in carriers that fit under a seat. Costs run from $95 to $125 each way, depending on the airline. Pets that do not fit under the seat can travel as cargo, but the number of airlines that offer that service has dropped because of the pandemic.

International travelers have a different hurdle to consider: Rules the Centers for Disease Control and Prevention imposed in July ban people from importing dogs from countries considered at high risk for rabies. That list includes more than 100 countries in Africa, the Americas, the Caribbean, Asia, the Middle East, and Eastern Europe. The CDC says travelers going to one of those countries should leave their dogs at home. Without a special permit, dogs will not be allowed back into the United States.

“They can’t go on vacation and take their dog to Belize,” said Angela Passman, a member of the International Pet and Animal Transportation Association and owner of World Pet Travel. “[If] they take their dog to Belize, it doesn’t come home.”

People looking to fly their pets, she said, need to make sure the airline will carry them. And if they’re looking to travel internationally, they must confirm the pet would be allowed back into the country.

“Just be careful,” Passman said. “I can’t stress it enough.”

Check how your hotel defines “pet-friendly”

Finding a hotel, Airbnb or other rental that accepts animals is a demanding task on its own, but figuring out how different properties define “pet-friendly” is an additional challenge.

Halliburton, the BringFido executive, said some hotels roll out the red carpet for pets, with amenities such as canine massage and gourmet room service.

As part of its pet-friendly expansion, Hilton teamed up with Mars Petcare to pilot a digital service that lets hotel guests at some Home2 Suites and Homewood Suites reach experts in pet health, wellness and behavior during their stay. Many of those branded hotels also have treats, bowls and waste bags — as well as recommendations on activities for animals — available at the front desk.

Even without a special program, many hotels allow animals to stay (for a fee) with some ground rules. Within a hotel brand, every location might welcome pets, or individual property owners may be able to decide if they will allow them. Prices might vary within the same chain.

On Airbnb, some listings have pet fees and strict rules, while others don’t mention either. Prospective visitors need to check the rules before they rent. The platform recently rolled out changes to entice more hosts to accept pets in their listings. BringFido’s rentals flag which properties charge pet fees and if they allow big dogs or restrict the number of pets that can stay.

“It’s very difficult to find the information that we have on our site on Vrbo or Airbnb,” Halliburton said.

Amy Burkert, founder of the site GoPetFriendly, said travelers need to find out if their accommodation has weight limits, a maximum number of pets, whether the pet can be left unattended and whether there are breed restrictions. Cat owners should also check specifically for restrictions concerning their pets.

“Pet-friendly doesn’t necessarily translate into cat-friendly,” she said.

Avoid cleaning charges in rental cars

Most rental car companies allow pets, but some, such as Avis, advise calling individual pickup locations to make sure. Some companies require pets to be kept in carriers. Others just say the car has to be clean and odor-free. If not, a cleaning charge applies.

Avis offers a list of suggestions for avoiding extra fees, including getting a pet groomed before bringing them in a rental car, choosing a cloth interior to make vacuuming easier, avoiding mud, leaving baking soda in the car and using a lint roller daily.

Burkert said her tip is to get an inexpensive shower curtain, thread the holes into the car’s headrests and cover whatever area the pet will sit in.

Take your small pet on the rails

Amtrak allows dogs and cats that weigh up to 20 pounds, including their carriers, on most routes for trips up to seven hours. Pets are limited to coach and Acela business class. The cost is $26. Reservations should be made in advance, since there is a limit to how many pets can be on one train.

Practice mealtime manners for restaurants

Burkert frequents restaurants with her mixed-breed dog, Myles. When she gets up to leave, she said, fellow customers will often say they didn’t even realize she had a pet.

“That’s exactly what I wanted,” she said.

She trained him at home by teaching him to stay on his place — a piece of a yoga mat — and then progressed to practicing at park picnic tables and off-hour coffee shops and restaurants. When they do go out to eat, she brings a toy stuffed with frozen dog food, water, a water bowl and a bully stick to chew on.

Still, Burkert said, dogs can have bad days: “You always have to be ready to get up and leave.”

She recommended checking restaurant websites and calling ahead to make sure they allow pets in outdoor areas (and that outdoor areas are even open). Breweries are the rare establishments that will allow pets inside, though that is not guaranteed.

Keep pet safety in mind on the road

Gabrielle Fadl, the medical director of Bond Vet in Brooklyn, said the safest way for pets to travel in cars is to put them inside carriers or crates. There are also seat belts made for dogs that don’t fit into crates.

In the days leading up to a trip, Fadl said, owners should leave the crate or carrier out and occasionally leave snacks in them to create positive associations. Traveling with a familiar blanket could help ease stress on the trip, too.

It is good to stop every three to four hours to give pups a break. If they are anxious, restless, panting or whining, those might be signs they need to stop sooner. Mary Burch, who directs the American Kennel Club’s canine manners program, said rest breaks should include a 10-to-15-minute walk and fresh water. Burch said the pet should have sufficient air circulation wherever they are sitting, and a pet might be more comfortable near an air conditioning vent during a long trip.

Make a medical checklist

If a pet is flying, owners should make sure they know whether the airline will require a health certificate and how long in advance it can be issued, Fadl said.

She said older pets should get checked before a trip to make sure the stress of traveling won’t be harmful. Owners should bring up any potential travel-related issues with their vet in advance.

“If your pet gets nauseous or anxious, there are medications that can help make it an easier trip for all parties involved,” Fadl said.

The pet’s packing list should include any medications they are taking, as well as prescription refills in case of an emergency.

Burch said a medical folder should also include vaccination records and a rabies certificate, records of any health issues, a health certificate, the pet’s microchip number, their veterinarian’s contact information and the number for Animal Poison Control. She said dogs should wear a tag with identification and a contact number while on a trip.

Fadl suggested searching in advance for emergency vet facilities in a destination or along the way in case of illness or injury. While regular offices might not have slots for an appointment, some emergency clinics might be able to see a traveling pet at the last minute.

“Most veterinary practices are going to be booked out for quite some time,” she said.