Kuala Lumpur Subang Airport (KLSA) is a regional airport located in Subang, Selangor, Malaysia. It was first established in 1965, when the Malaysian government decided to build a new airport in the area to replace the existing Kuala Lumpur International Airport (KLIA) which had become overcrowded. The new airport was named Kuala Lumpur Subang Airport, in honour of the nearby Subang River.

KLSA is currently the ninth busiest airport in Malaysia, with over 8 million passengers per year. The airport has a total of three runways, which are all equipped with CAT II lighting systems, allowing for night operations. The airport's three main terminals are Terminal 1, Terminal 2, and the Satellite Terminal. The airport also has two cargo terminals, which are used to handle airfreight and mail.

KLSA is serviced by many major airlines, including AirAsia, Malindo Air, Malaysia Airlines, Singapore Airlines, and Thai AirAsia. The airport is also used by budget airlines such as Firefly, Jetstar Asia, and Scoot. In total, KLSA has over 120 scheduled flights every day.

The airport's three letter code, SZB, was determined by the International Air Transport Association (IATA). The SZB code was chosen as a combination of the airport's three-letter city code (KUL) and the first two letters of the airport's name (SU).

Kuala Lumpur Subang Airport is an important part of Malaysia's aviation infrastructure. In addition to providing regional and international flights, the airport is also used as a base for regional military operations by the Royal Malaysian Air Force. The airport is also used by the Malaysian government as a hub for emergency and disaster relief operations.

Kuala Lumpur Subang Airport is dedicated to providing a safe and enjoyable experience to its passengers. The airport is well-maintained and equipped with modern amenities, such as free Wi-Fi, charging stations, and comfortable seating areas. KLSA is also an eco-friendly airport, and is committed to reducing its environmental impact by utilizing sustainable practices such as energy-efficient lighting and water recycling systems.