(AP)- Five puppies learning to serve as assistance dogs had a howling good time during a training exercise at Detroit Metropolitan Airport. The pooches and their trainers walked Tuesday through a TSA checkpoint, rode an elevated tram and boarded an airplane on the visit. It was part of an effort to acclimate the dogs to one of the many settings they may experience later in life. The training was led by a nonprofit that oversees the custom training of puppies that later become assistance dogs for people with disabilities. The trainers also take the puppies to grocery stores, libraries, restaurants and doctor’s appointments.