Over the busy holiday travel season, passengers at George Bush Intercontinental Airport (IAH) were greeted by man’s best friend.

About 35 specially trained dogs helped ease the stress for the 1.85 million people who traveled through the airport over the holiday season. The United Paws program created by United Airlines takes more than 230 comfort dogs to seven airports over three days with a mission to reduce stress and deliver smiles to customers.

United Airlines selected Bush Intercontinental Airport as one of only a few airports to pilot the program during the 2014 holiday travel season and brought the program back this year due to positive feedback

"In ways large and small, all of us at United want to bring a bit of comfort and joy to our customers during this busy season of travel," said Tom O'Toole, United's senior vice president and chief marketing officer. "We introduced comfort dogs during the holiday season last year, and they were very popular with our customers, so we're bringing them back at more airports this year."

"United Paws is a wonderful program that comes at just the right time for some holiday travelers who may be experiencing a bit of anxiety or stress," says Veterinary Consultant Dr. Walter Woolf. "Research shows that just petting a dog releases oxytocin, the hormone associated with bonding and affection, and also decreases levels of stress, helps us breathe easier and lowers our blood pressure. I've experienced this recently and think this is a wonderful idea for holiday travelers."

The therapy dogs must pass the American Kennel Club's Canine Good Citizen program, which is recognized as the gold standard for dog behavior. The therapy dogs are also trained to ride elevators and to behave in crowds.