WAAS builds on Horizon's previous advances – made in conjunction with its sister airline, Alaska Airlines – in Flight Management System (FMS) technology, such as Required Navigational Performance (RNP) and Global Positioning System (GPS) satellite networks. In 2006, Horizon became the first regional carrier to be certified for RNP approaches, which use a combination of onboard navigation technology and GPS. WAAS takes that a step further by using additional satellites that monitor GPS satellite signals; it then corrects for any errors in GPS satellite position. 

The new WAAS instrument approach is known as "localizer performance with vertical guidance" (LPV). Unlike RNP approaches, which are only available for use at airports after an extensive certification process, WAAS approaches can be used at any airport where the navigation database has been updated. 

There are now more LPV approaches available in U.S. airspace than Instrument Landing Systems (ILS) approaches, which involve using an older, ground-based radio signal system for landings in lower-visibility weather. One LPV advantage is that it doesn't rely on ground-based equipment susceptible to outside factors such as weather or power outage.

Currently, Horizon has one WAAS-equipped Q400, with a flight management system developed by Universal Avionics, a manufacturer of advanced avionics equipment based in Tucson, Ariz. The Federal Aviation Administration (FAA) has agreed to support WAAS upgrades on six more Horizon Q400s. In return, Horizon will provide the FAA with flight data on 300 legs of flying, so the agency can determine the full value of WAAS technology. 

Horizon serves 48 cities throughout Arizona, California, Oregon, Washington, Idaho, Montana, Nevada, Baja California Sur (Mexico), and British Columbia and Alberta (Canada). Together, Horizon Air and Alaska Airlines serve more than 90 cities and are subsidiaries of Alaska Air Group, Inc.