Mills Field

The City and County of San Francisco first leased, from the Darius Ogden Mills estate, 150-acre (61-hectare) at the present airport site on March 15, 1927, for what was then to be a temporary and experimental airport project. San Francisco held a dedication ceremony at the airfield, officially named the Mills Field Municipal Airport of San Francisco, on May 7, 1927, on the 150-acre (61-hectare) cow pasture. The land was leased from the Mills Estate in an agreement made with Ogden L. Mills who oversaw the large tracts of property originally acquired by his grandfather, the banker Darius O. Mills. San Francisco purchased the property and the surrounding area expanding the site to 1,112 acres (450 hectares) beginning in August 1930. The airport's name was officially changed to San Francisco Airport in 1931 upon the purchase of the land. "International" was added to the name at the end of World War II as overseas service rapidly expanded.

Early operations

The earliest scheduled carriers at the airport included Western Air Express, Maddux Air Lines, and Century Pacific Lines. United Airlines was formed in 1934 and quickly became the key carrier at the airport, with Douglas DC-3 service to Los Angeles and New York beginning in January 1937. A new passenger terminal opened in 1937, built with Public Works Administration funding. The March 1939 Official Aviation Guide shows 18 airline departures on weekdays—seventeen United flights and one TWA flight. The August 1952 chart shows runway 1L 7,000 feet long, 1R 7,750 feet, 28L 6,500 feet, and 28R 8,870 feet.

In addition to United, Pacific Seaboard Air Lines flew between San Francisco and Los Angeles in 1933; the Bellanca CH-300s flew San Francisco–San Jose–Salinas–Monterey–Paso Robles–San Luis Obispo–Santa Maria–Santa Barbara–Los Angeles. Competition with United led Pacific Seaboard to move all of its operations to the eastern U.S., and rename itself Chicago and Southern Air Lines (C&S). It became a large domestic and international air carrier. Chicago & Southern was acquired by and merged into Delta Air Lines in 1953, giving Delta its first international routes. Delta used the route authority inherited from C&S to fly one of its first international services operated with Convair 880 jet aircraft from San Francisco to Montego Bay, Jamaica, and Caracas, Venezuela, via intermediate stops in Dallas and New Orleans in 1962.

World War II

During World War II, the airport was used as a Coast Guard base and Army Air Corps training and staging base. The base was called Naval Auxiliary Air Facility Mills Field and Coast Guard Air Station, San Francisco. Pan American World Airways (Pan Am), which had operated international flying boat service from Treasure Island, had to move its Pacific and Alaska seaplane operations to SFO in 1944 after Treasure Island was expropriated for use as a military base. Pan Am began service from SFO after World War II with five weekly flights to Honolulu, one of which continued to Canton Island, Fiji, New Caledonia, and Auckland.

International operations

The first service by foreign carriers was on Australian National Airways (ANA) Douglas DC-4s flown by British Commonwealth Pacific Airlines: Sydney–Auckland–Fiji–Kanton Island–Honolulu–San Francisco–Vancouver, BC. The first flight left Australia on September 15, 1946. In 1947 Pan American World Airways began its "round the world" flights from SFO to Guam, Japan, the Philippines, China and other countries; Pan Am also flew to Sydney from SFO. The year 1947 saw the start of United Airlines Douglas DC-6 flights to Hawaii and Philippine Airlines flights to Manila.

TWA began flying Lockheed Constellations (L-1649A's) nonstop to London Heathrow and Paris Orly in 1957. In 1954 Qantas took over the ANA/BCPA route from SFO to Sydney; starting in 1959 their Boeing 707s flew to Sydney via Honolulu and Nadi, Fiji, and in the other direction to New York and London. Pan Am scheduled Boeing 707-320s from Tokyo nonstop to SFO (winter only at first) starting in 1960–61; the westbound nonstops had to await the longer range Boeing 707-320B. British Overseas Airways Corporation (BOAC, a predecessor of British Airways) arrived in 1957; in 1960 its Bristol Britannias flew London–New York City–San Francisco–Honolulu–Wake Island–Tokyo–Hong Kong as part of BOAC's around-the-world service. By 1961 BOAC had replaced the Britannias with Boeing 707s that did not require the fuel stop at the Wake Island Airfield. Japan Airlines (JAL) arrived at SFO in 1954; in 1961 it was flying Douglas DC-8s San Francisco–Honolulu–Tokyo. In 1961 Lufthansa had begun serving SFO with Boeing 707s flying San Francisco–Montreal Dorval Airport–Paris Orly Airport–Frankfurt three days a week. Lufthansa operated Boeing 720Bs on this routing in 1963 along with Boeing 707s to Frankfurt via Montreal and London Heathrow Airport. Pan Am/Panagra service from SFO to South America was taken over in the late 1960s by Braniff International, which operated Douglas DC-8-62s to SFO after Braniff's acquisition of Panagra.