Portland International Airport (IATA: PDX, ICAO: KPDX) is the largest airport in the U.S. state of Oregon, accounting for 90% of passenger travel and more than 90% of air cargo. Located 4 mi (6 km) northeast of Portland, close to the Columbia River, and 20 minutes by car from Downtown, PDX is connected to the downtown business and arts districts by light rail (MAX) Red Line.

PDX has direct connections to major airport hubs throughout the United States, plus direct international flights to Canada, Mexico, Japan, and Germany. It is also a hub for flights to smaller cities in Oregon, Washington, Idaho, Montana, California and Nevada. General aviation services are provided at PDX by Flightcraft. The Oregon Air National Guard has a base located on the south side of the property.

Portland International Airport is a major hub for Alaska Airlines and Horizon Air, mainly located on Concourse A, B, and C. PDX was identified as the top airport for business travelers in the United States in the October 2006 issue of Condé Nast Traveler magazine. Research for the article identified the airport's easy access (including light rail service), shopping and free wireless Internet access as factors leading to the selection.