In 1916, Turnhouse Aerodrome opened as the northernmost British air defence base in World War I used by the Royal Flying Corps. In 1918, the Royal Air Force was formed and the airfield was named RAF Turnhouse and ownership was transferred to the Air Ministry. From 1925, the small base was used to house the 603 (City of Edinburgh) Squadron, which consisted of DH 9As, Westland Wapitis, Hawker Harts, and Hawker Hind light bombers. All the aircraft used a grass airstrip. In 1939, when the Second World War broke out, RAF Fighter Command took control over the airfield and a runway of 3,900 ft (1,189 m) was paved to handle the Supermarine Spitfire. During the Battle of Britain, 3, 65, and 141 Squadrons were present at the airbase. After 1945, when WW2 ended, the airfield remained under military control. It was officially opened for commercial traffic on 19 May 1947. The first commercial flight to use the airport was a British European Airways service from London (Northolt) to Shetland, with Edinburgh and Aberdeen being intermediate stopping points. The aircraft was an 18-seat Douglas C47. On 1 April 1971, the British Airports Authority (BAA) took over ownership of the airport, at a time when the original terminal building was running at about eight times its design capacity. Immediate improvements to the terminal were cosmetic, such as extra seating and TV monitors for flight information, and it took two years for plans to be proposed for a completely new terminal and runway redesign. Public consultation on planning started in November 1971 and ended in February 1972. The initial stages of the redevelopment began in June 1973; they included a diversion of the River Almond. Work on the new terminal building, designed by Sir Robert Matthew, started in March 1975, and the building was officially opened by Queen Elizabeth II on 27 May 1977. International service from Edinburgh began in 1962 with direct service to Dublin, but for many years international flights were charter and private only. This started to change during the late 1970s, with direct services to continental Europe (Amsterdam, 1975). By the mid-1980s, direct routes included Paris, Düsseldorf, Brussels, Frankfurt and Copenhagen, but direct transatlantic flights were not yet possible as Glasgow-Prestwick was the only "designated gateway" in Scotland under the US-UK Bermuda II Agreement. By the time BAA had been privatised in 1987, Edinburgh Airport handled over 1.8 million passengers each year; compared to the 681,000 passengers handled in 1971 when BAA first took control of the airport. RAF Turnhouse was operational near the passenger terminal of the airport for all of the post-war period but was finally closed in 1997. On 19 October 2011, BAA Limited announced its intention to sell the airport, following a decision by the UK's Competition Commission requiring BAA to sell either Glasgow Airport or Edinburgh Airport. BAA announced on 23 April 2012 that it had sold Edinburgh Airport to Global Infrastructure Partners (GIP) for a price of £807.2 million, equivalent to £1161 million in 2025. In 2013, a further extension to the passenger terminal was announced, taking the terminal building up to the Edinburgh Airport tram stop. The Edinburgh Trams opening in May 2014 created the first rail connection to Edinburgh Airport. Whilst the number of passengers has increased, the number of flights decreased in 2014 due to planes operating at a higher capacity. A new £25million expansion project involving the construction of a new 6,000 m2 (65,000 sq ft) building, housing a security hall and retail areas, was also completed. In February 2016, consultancy firm Biggar Economics announced that Edinburgh Airport contributes almost £1 billion annually to the Scottish economy. As part of the expansion works, Runway 12/30 was officially withdrawn from use on 29 March 2018.