Phoenix Sky Harbor International Airport is a civil–military public airport 3 miles east of downtown Phoenix, in Maricopa County, Arizona, United States. It is Arizona's largest and busiest airport; among the largest commercial airports in the United States, PHX was the 8th-busiest airport in the United States and 22nd-busiest in the world in 2021. The airport serves as a hub for American Airlines and a base for Frontier Airlines and Southwest Airlines.

Maricopa County is in the south-central part of the U.S. state of Arizona. As of the 2020 census the population was 4,420,568, or about 62% of the state's total, making it the fourth-most populous county in the United States and the most populous county in Arizona, and making Arizona one of the nation's most centralized states. The county seat is Phoenix, the state capital and fifth-most populous city in the United States.