Seletar Airport (XSP) is Singapore's oldest aerodrome in continuous operation, first opened in 1928 as RAF Seletar, a Royal Air Force base and the RAF's first airfield east of India. The site was chosen in 1923 from land in the island's northeast, and the air force began using it before it formally opened on February 28, 1928. It briefly served as Singapore's first international civil airport when commercial flights began there in February 1930, a role it held until Kallang Airport took over civilian traffic in 1937. Pioneer aviators who stopped over during the era of long-distance flying included Amy Johnson, Charles Kingsford-Smith, and Jean Batten.

The RAF withdrew in 1971, transferring control to Singapore. Over subsequent decades the airport transitioned from military use to general aviation, becoming home to flight training clubs, charter operators, and maintenance, repair, and overhaul firms. A runway extension was completed in 2012. The surrounding area was developed into the Seletar Aerospace Park, which today houses more than 60 aerospace companies. A new S$80 million passenger terminal opened on November 19, 2018, six times larger than its predecessor and rated for up to 700,000 passengers per year, consolidating all commercial turboprop services onto the field.

Today, XSP sits approximately 16 km northwest of Changi Airport and functions as a deliberate pressure valve for it, handling turboprop-sized aircraft, business jets, medical evacuations, freighter operations, and flight training. Firefly operates the airport's sole scheduled passenger route, an ATR-72 service to Kuala Lumpur Subang. The airport is owned by the Civil Aviation Authority of Singapore and managed by the Changi Airport Group. Its compact single-runway layout, runway 03/21 at 1,840 metres, gives it a distinctly intimate operational character compared to its famous neighbour.