A feral horse is a free-roaming horse of domesticated ancestry. As such, a feral horse is not a wild animal in the sense of an animal without domesticated ancestors. However, some populations of feral horses are managed as wildlife, and these horses often are popularly called wild horses.
The airport is served by Delta, Alaska Air/Horizon Air, United and Allegiant with flights to Seattle, Portland, San Francisco, Minneapolis/St. Paul, Denver, Salt Lake City, Los Angeles, Las Vegas and Mesa, Arizona.
Cool data! Another neat thing to look at would be how the airline networks have changed over time. And not to nitpick, but Alaska Airlines has most of their flights going through Seattle-Tacoma, not Portland. Seatac is their hub airport.