Cheryl Maduzia’s job for a sales and marketing company in Jacksonville, Fla., has her on the road to meet clients several times a month. And when she has to catch a flight, Maduzia’s 33-pound dog, Katie, goes along.

But before Maduzia checks in, she checks Katie into Pet Paradise, a 24-hour pet boarding “resort” on airport property.

“I like it because I can drop Katie off at any time and pick her up at any time,” Maduzia said via email from a flight to Seattle. “Today I dropped her off at 5 a.m., which I can’t do at a kennel that isn’t open 24 hours. … I’d have to either drop her off the night before or take a later flight.”

Founded in 2002 by Fred Goldsmith, the Pet Paradise network now includes branches at or very close to the airports in New Orleans; Charlotte, N.C.; Houston (both Hobby and Bush Intercontinental); and Hartsfield-Jackson in Atlanta. The Pet Paradise there is located with Park n’ Fly Plus, and offers valet service and luggage check-in.

Each Pet Paradise “resort” offers boarding as well as daycare. Amenities include climate-controlled accommodation and indoor-outdoor play areas. Grooming and training services are available, and some locations have swimming pools and offer discounts on airport parking.

“We’re running a hotel, but instead of people, we check in dogs, cats, the occasional pot-bellied pig and, once, some llamas,” Goldsmith said. “And we use the same kind of occupancy and revenue algorithms you use in the hotel business. We track everything the same way.”

Daily rates for the airport spas pencil out to a dollar or two more per night than a comparable kennel in town, he said.

For business travelers like Maduzia, the 24-hour convenience and optional extras are worth it. In addition to getting more playtime for Katie, Maduzia often has her bathed and, on special occasions, upgraded to a suite.

“I figure if I’m on vacation, staying at a nice hotel, then she deserves the same,” Maduzia said.

Pet Paradise isn’t the only company offering upscale boarding services at airports. Paradise4Paws has branches at Chicago O’Hare and Midway airports and at Dallas/Fort Worth International Airport (DFW), near one of the long-term parking lots on airport property.

“We think it’s a great amenity to provide to our passengers, especially business travelers,” said DFW spokesman David Magaña, “In addition to being there 24/7, they have some of ‘best in class’ services that we like our concessionaires to offer.”

Those include ‘pawdicures” and other grooming services, massage therapy and a bone-shaped splash pool. Busy travelers can even arrange to have a pet picked up or delivered curbside.

All for a fee, of course.

According to the American Pet Products Association, pet owners spent $4.16 billion on grooming and boarding last year. The trade organization expects that number to be $4.54 billion this year.

Pampering pets and their globe-hopping owners has turned out to be good business at Minneapolis/St. Paul International Airport as well.

In 2008, the airport found itself with an empty industrial building and no market-rate renters in sight, “so we put out an RFP for a higher-end pet boarding service,” said Eric Johnson, the airport’s director of commercial management and airline affairs.

The winning bid came from the Animal Humane Society, which proposed a revenue-generating operation called Now Boarding.

In addition to kennel services, the facility offers training classes, outdoor play areas and an indoor pool. For people, it has parking and shuttle service to and from the terminals.

“The prices are right in line with what you’d pay in town at the higher-end boarding facilities,” said Johnson, who occasionally leaves his own dog, a yellow lab named Bella, at Now Boarding. “And the parking is cheaper than right at the airport.”

Now Boarding did about 1.5 million in sales last year, which translated into $176,000 in rental income for the airport. “They’ll probably do well over that this year,” Johnson said.

Other airports are joining the pack.

The Denver City Council is close to signing a contract for a pet boarding facility for dogs and cats that will open on airport property late this year or early in 2014.

According to airport spokesman Heath Montgomery, in addition to being convenient for pet owners, the business will create about 10 jobs, and generate about $92,000 in annual rent for the airport and more than $31,000 in annual sales tax for the City and County of Denver.

(My story about pet boarding at airports first appeared on the CNBC Road Warrior)