This new 32,000-square-foot facility relieves passenger congestion at Sea-Tac International Airport. The Concourse D Annex utilizes space more effectively for passengers waiting for flights, reduces the amount of time passengers spend waiting for a plane to arrive at a gate, saves greenhouse gas emissions from idling aircraft and ultimately saves airlines fuel. The Annex includes six holdroom gates where passengers are shuttled to and from an aircraft parked away from the terminal building. Amenities for passengers include concessions, electric charging stations, free airport WiFi and restrooms. Passengers walk through a gate door to a waiting shuttle which takes them to the aircraft parked away from the terminal.