More than 100 airlines operate from the airport, with flights to destinations in Asia, Oceania, Africa, Europe, the Middle East, and North America.

With Singapore's strategic location being a favourable destination for high demand layovers, the airport also serves as a focus city for Qantas, as well as the flagship cargo hub for FedEx Express in Asia.

While the ICAO code for Changi airport is WSSS, the third runway (02R/20L) is originally part of the Changi Air Base (East) operated by the Republic of Singapore Air Force (RSAF) and technically carried a different ICAO code WSAC.

It had opened in 1955 with a single runway and a small passenger terminal, having itself replaced the previous Kallang Airport that began operations in 1937.

After extensive studies, a decision was made in 1972 to keep the airport at Paya Lebar, as recommended by aviation consultants.

[26] Concerned that the existing airport was located in an area with potential for urban growth, which would physically hem it in on all sides, the government subsequently decided in 1975 to build a new airport at the eastern tip of the main island at Changi, at the existing site of Changi Air Base.

[26] The original master plan for Changi Airport involved constructing a dual-terminal and dual-runway configuration over two phases with provisions for another two passenger terminals in the future.

Phase 1 included the construction for the first passenger terminal, the first runway reusing and upgrading the main runway of Changi Air Base, 45 aircraft parking bays, support facilities and structures, including a large maintenance hangar, a fire station, workshops and administrative offices, an airfreight complex, two cargo agents buildings, in-flight catering kitchens and an 80 m (260 ft) control tower.

The airport ended its first year of operations with 12.1 million passengers, close to 200,000 tonnes of air freight handled and 63,100 aircraft movements.

The former Transport Minister Khaw Boon Wan said that the Changi Terminal 5 project was delayed by at least 2 years as a result of the COVID-19 pandemic.

[39] Jewel Changi Airport, which opened on 17 April 2019, is a nature-themed entertainment and retail complex interconnecting Terminals 1, 2 and 3.

[48] Due to Singapore's large electronics sector, electrical components constitute a significant part of the total cargo traffic handled at the airport.

The top five cargo markets for the airport were China, Australia, Hong Kong, United States and India.

In March 2008, prior to the full effect of the financial crisis of 2007–2010 on the global economy, the airport was predicted to handle 50 million passengers by 2012[54] due to the opening of casinos in Singapore and the phased liberalisation of the ASEAN aviation sector.

[61] Terminals 1 and 3 remained open for passengers throughout, but were closed to the general public on 12 May 2021 along with Jewel, reopening on 1 September 2021.

The refurbished terminal features nature-themed decorations and a 14m-tall digital waterfall display called the Wonderfall.

[67] It involves the deployment of about 2,600 Certis Cisco personnel, including armed Auxiliary Police Officers and unarmed aviation security officers to perform tasks such as screening checked baggage, controlling access to restricted areas, and screening passengers before they board their aircraft.

[69][70] Prohibited items include sharp/blunt objects and liquids/gels/aerosols above 100ml, however people are aware of and it is no longer enforced by Certis CISCO officers.

[70] Sources:[87][88][89][90][91] In 2024, China was the largest market for the airport, followed by Indonesia, Malaysia, Australia, Thailand, India, Japan, Philippines, Hong Kong and Vietnam.

Kuala Lumpur was the top destination for travellers in the airport, followed by Bangkok, Jakarta, Denpasar, Hong Kong, Manila, Tokyo, Shanghai, Seoul, and Taipei .

At a distance of about 20 km (12 mi), the expressway was built almost entirely on reclaimed land, thus minimising disruptions to the existing road network in Singapore's eastern coasts.

[citation needed] Despite the four main passenger terminal buildings being relatively close to each other, the CAAS (Civil Aviation Authority of Singapore) decided to build the Changi Airport Skytrain people-mover system to facilitate quicker and more convenient transfers between the terminals for travellers.

The system was upgraded in 2007 with new technologies supplied by Mitsubishi, connecting to Terminal 3 and separating checked-in passengers from the general public on distinct tracks.

[254] The airport is connected to the Mass Rapid Transit (MRT) network via a two-stop branch of the East West line from Tanah Merah MRT station, consisting of two stations: Expo, serving the nearby Singapore Expo site; and Changi Airport.

Direct, one-train service to the downtown and western parts of Singapore was initially in operation when the station opened on 8 February 2002.

This was replaced by the current shuttle service between Tanah Merah and Changi Airport via Expo on 22 July 2003,[255] when it was found that passenger demand for this route was low.

As announced in the LTA's Land Transport Masterplan, the new Thomson–East Coast line will be extended to Changi Airport Terminal 5 and to the current Changi Airport station, with the current EWL Branch line being converted to be part of the TEL.

[257] In addition to buses for passengers serving the terminals, SBS Transit also provides bus services for staff at the Changi Airfreight Centre.

Due to the large distance covered by the complex itself (over 2 km (1.2 mi) end-to-end), bus stops are located inside the restricted-access area, and auxiliary police routinely board at the final stop before the complex (at the Police Pass Office) to check passengers for their right to enter.

Along the way is a 1 km (0.62 mi) long Changi Jurassic Mile where there is a permanent display of life-sized dinosaurs.