Whether you hate to fly or just dread the security lines, airports can be stressful places. There's the race for the gates, the lugging of luggage and the general anxiety of going from one place to another and getting there safe and sound.

To make the road to the friendly skies more soothing, dozens of airports have called upon therapy dogs to stroll the concourses. These waggy-tailed ambassadors often wear brightly colored vests emblazoned with "Pet me!" inviting weary travelers to let their anxieties fade with some simple canine counseling.

The idea was launched after Sept. 11, 2011, when a volunteer at the Mineta San José International Airport brought her certified therapy dog, a boxer/great Dane mix named Orion, to the airport hoping it would calm passengers' fears about flying, reports USA Today. San José now has more than a dozen teams of dogs and handlers and has been used as a model for many airports around the country.

"We've had many very touching encounters with airport employees and travelers," said Kyra Hubis, who visited the airport with her golden retriever, Henry James. "It's especially poignant to see soldiers being deployed hugging Henry James and telling him to 'take care of the house' while they're gone."

Now, airports from Miami to San Francisco to Oklahoma City to Charlotte, employ these furry diplomats. The pets are all sizes and breeds. The only requirements are that they love lots of petting and hugging and have to be certified by a national agency.

And surprisingly, they're not all dogs. The latest member of the airline ambassadors is a tutu-wearing pig! Take a look at our roundup below.

Lucy the terrier is a therapy dog at Charlotte-Douglas airport Lucy the terrier is ready to greet passengers in Charlotte. (Photo: Charlotte-Douglas International Airport - CLT/Facebook)

therapy dog Gracie at San Jose airport Therapy dog Gracie walks through San Jose International Airport, which piloted the airport therapy dog program. (Photo: San Jose International Airport/Facebook)

Toby is a member of the Wag Brigade at the San Francisco International Airport.Toby is a member of the Wag Brigade at the San Francisco International Airport. (Photo: San Francisco International Airport)/Facebook)

Annie the therapy dog greets an airport traveler in Denver Annie is part of the Canine Airport Therapy Squad at the Denver International Airport. (Photo: Denver International Airport)

Vegas therapy dog at LAX airport Vegas is a member of the Pets Unstressing Passengers (PUP) program at LAX. (Photo: Los Angeles International Airport)/Facebook)

LiLou the therapy pig LiLou the pig is the newest member of the Wag Brigade at San Francisco's airport. (Photo: San Francisco International Airport/Facebook)

Bosco takes a break during a long day of greeting travelers at Will Rogers World Airport in Oklahoma City. Bosco takes a break during a long day of greeting travelers at Will Rogers World Airport in Oklahoma City. (Photo: Will Rogers World Airport/Facebook)

Casey the golden retriever strolls the concourses at Miami International Airport. Casey the golden retriever strolls the concourses at Miami International Airport. Some pet therapy dogs have their own baseball-type cards for the people they meet. (Photo: Miami International Airport/Facebook)

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.