Sydney Kingsford Smith International Airport — Sydney (Mascot), Australia

Few major airports sit as close to their city's center as SYD, whose runways at Mascot lie only a handful of kilometers from Sydney's harbor and skyline, making for a strikingly short taxi or train ride into downtown. Its official name honors Charles Kingsford Smith, an Australian aviator who completed one of the first trans-Pacific flights in the 1920s and remains a celebrated figure in the country's aviation history. As Qantas's largest base and effective home, Sydney Airport anchors the carrier's domestic and international networks, and it ranks as Australia's busiest airport by a wide margin. A strict overnight curfew limits operations given the facility's proximity to residential suburbs, a constraint that has shaped debate for decades over whether Sydney needs a second major airport. Three runways, including a parallel pair, handle traffic across international, domestic, and regional terminals connected by rail to the wider city.