Early years

Originally, the airport was built by the United States military during the military allied occupation of Iceland in World War II, as a replacement for a small British landing strip at Garður to the north. It consisted of two separate two-runway airfields, built simultaneously just 4 km (2.5 mi) apart. Patterson Field in the south-east opened in 1942 despite being partly incomplete. It was named after a young pilot who died in Iceland. Meeks Field to the north-west opened on 23 March 1943, where the airport is still located today. It was named after another young pilot, George Meeks, who died on the Reykjavík airfield. Patterson Field was closed after the war, but Meeks Field and the adjoining structures were returned to Iceland's control and were renamed Naval Air Station Keflavik, named after the nearby town of Keflavík.

In 1949, a passenger terminal was built by the Lockheed Overseas Aircraft Service. In its first years the passenger terminal was mostly used for troop transport as well as transatlantic technical stops; civilian airlines Icelandair and Loftleiðir were still based at the smaller Reykjavík Airport.

In 1951, the U.S. military returned to the airport under a defence agreement between Iceland and the U.S. signed on 5 May 1951.

Development since the 1960s

The presence of foreign military forces in Iceland under the NATO-sponsored Iceland–U.S. Defense Agreement of 1951 was controversial in Iceland, which had no military forces other than the Icelandic Coast Guard. During the 1960s and 1970s, rallies were held to protest the U.S. military presence in Iceland (and in particular at Keflavík), and every year protesters walked the 50-kilometre (30 mi) road from Reykjavík to Keflavík and chanted "Ísland úr NATO, herinn burt" (lit. 'Iceland out of NATO, the military away'). The protests were not effective.

Transition of flights from Reykjavík

Until the 1960s, the airlines Icelandair and Loftleiðir Icelandic were solely based at the smaller civilian Reykjavík Airport, which is situated within the city and did not have military access restrictions.

Loftleiðir took delivery of its first Canadair CL-44 aircraft in 1964 and Icelandair took delivery of a Boeing 727 as Iceland's first jet aircraft in 1967. These new aircraft were considered too large for regular operation on the shorter runway at Reykjavík Airport. Both airlines began operations of their new larger aircraft from the longer runway at Keflavík Airport, greatly increasing the civilian passenger traffic through the Keflavík terminal.

By the 1970s, almost all international traffic was moved to Keflavík, relegating Reykjavík Airport to serving domestic services and limited short-haul international traffic to Greenland and the Faroe Islands. The road from Reykjavík to Keflavík was newly rebuilt and paved by 1965 which greatly improved access to Keflavík Airport from the city.

New passenger terminal

The original Keflavík passenger terminal built in 1949 was located within the NASKEF military air base. Travellers therefore had to pass through military checkpoints to reach their flights. The situation of having to pass through a U.S. military base in order to access the passenger terminal remained unchanged as civilian passenger numbers increased and was not considered ideal.

Subsequently, in April 1987 the Icelandic government finished construction of a relocated civilian terminal which was located on the north side of the airport. The new terminal had separate access from the military area and was accessible without passing through the military area. The new terminal was named after Leif Erikson who was the first European to arrive in North America (Flugstöð Leifs Eiríkssonar, "Leif Erikson Air Terminal").

Other history

The two 3,000-metre-long (10,000 ft) and 60-metre-wide (200 ft) runways were large enough to support NASA's Space Shuttle as well as the Antonov An-225. On 29 June 1999, Concorde G-BOAA flew from Heathrow Airport to Reykjavík (Keflavik airport). The Concorde had been there earlier. Due to its location, the airport is also an important diversion landing site for large aircraft in transatlantic ETOPS operations.

Since 2000

The terminal was extended with the opening of the South Building in 2001, to comply with the requirements of the Schengen Agreement. The North Building was enlarged and finished in 2007.

The United States military base, NASKEF, closed down in 2006 and was handed over to the Icelandic Government. The original Keflavík passenger terminal, built in 1949 and defunct since 1987, was demolished in 2018.

In 2014, a high-speed airport rail link to Reykjavík was proposed, which would be Iceland's first passenger railway. As of 2023, proposals have not progressed past the planning phase but the route is safeguarded in local and airport masterplans.

The airport was used as a hub by defunct airline WOW air (and earlier as Iceland Express) until it ceased operations on 28 March 2019.