SEATTLE – Self-driving wheelchairs have taken hundreds of passengers to their gates at Seattle-Tacoma International Airport, under a new program from Alaska Airlines. A testing period for the Whill autonomous wheelchairs began in August within the C and D concourses, an Alaska Airlines spokesperson said in an email. Passengers can get to their desired gate by selecting a stop on a touchscreen. The chairs have a baggage rack and sensors to detect obstacles, according to Whill.