SFO is the largest airport in the San Francisco Bay Area and the second-busiest in California, after Los Angeles International Airport (LAX). In 2023, it was the fourteenth-busiest airport in the United States and the 30th-busiest in the world by passenger count. It is the fifth-largest hub for United Airlines, functioning as the airline’s primary transpacific gateway, and is a major maintenance hub. It also serves as a hub for Alaska Airlines.