Tan Son Nhat International Airport — Ho Chi Minh City, Vietnam

Tan Son Nhat International Airport, serving Ho Chi Minh City on the site of what was once Saigon, ranks as Vietnam's busiest airport by a wide margin and carries a layered history stretching from French colonial aviation through its enormous expansion as a US military airbase during the Vietnam War. The chaotic helicopter evacuations from the airport and nearby rooftops in the closing days of April 1975, as Saigon fell to advancing North Vietnamese forces, remain among the most iconic images of that conflict's end. Decades later, SGN has grown into a critical node for Vietnam's export-driven economy and its rapidly expanding tourism sector, handling passenger volumes that now regularly exceed the airport's original design capacity and prompting long-term traffic and congestion concerns. To relieve pressure on SGN, Vietnam has been developing Long Thanh International Airport at a new site outside the city, intended eventually to take over much of the region's long-haul international traffic.