The airport opened on 15 October 1942, during World War II, and initially operated in conjunction with the Cabo Ruivo Seaplane Base: seaplanes performed transatlantic flights, and passengers were transferred onto continental flights operating from the new airport. As a neutral airport, it was open to both German and British airlines, and was a hub for smuggling people into, out of, and across Europe. It is widely referenced in the classic film Casablanca, whose plot revolves around an escape attempt to Lisbon airport. As such, it was heavily monitored by both Axis and Allied spies. Although Portugal was neutral, the airport was used by allied flights en route to Gibraltar, North Africa and Cairo. By 1954 the number of passengers reached 100,000. A 1951–1952 airport diagram shows four runways laid out at 45-degree angles: 1,350 m (4,429 ft) Runway 5, 1,024 m (3,360 ft) Runway 9, 1,203 m (3,947 ft) Runway 14, and 1,170 m (3,839 ft) Runway 18. Runways 5 and 36 were each later extended northward to a length of 1,999 m (6,558 ft). Major upgrades from 1959 to 1962 included a new runway capable of handling the first generation of jets, such as the Boeing 707 and Douglas DC-8. The first jet aircraft flight was an Air France Caravelle in 1960. In 1962 runway 02/20 came into use. It was 3,130 m (10,269 ft) long and would allow direct transatlantic flights. The first direct flight to New York was operated by TWA with a Boeing 707, who later operated the first Boeing 747 service in 1970. When TAP ordered the 747 in 1972, five large parking bays were built, and the terminal was enlarged. A major upgrade to the buildings and facilities commenced in 1983, and the first air bridges were added in 1991. Along with the airports in Porto, Faro, Ponta Delgada, Santa Maria, Horta, Flores, Madeira, and Porto Santo, the airport's concessions to provide support to civil aviation were conceded to ANA Aeroportos de Portugal on 18 December 1998, under provisions of decree 404/98. With this concession, ANA became responsible for the planning, development and construction of future infrastructure. The construction of Terminal 2 was concluded and operational since August 2007. Expansion of Terminal 1 with new boarding gates was concluded in 2011. A large new shopping and restaurant area, new airbridges and parking positions, a more efficient use of currently existing structures, and a new underground Lisbon Metro station were inaugurated in July 2012. In October 2010, easyJet opened a new base at Lisbon Airport, using Terminal 2 for departures. In 2022, the airline moved to Terminal 1. Between 2007 and 2013, Lisbon Airport underwent several structural and equipment improvements and expansions. These included the construction of Terminal 2, lighting and baggage claim refurbishment, new cargo facilities, fuel storage, north pier and boarding lounge, north bus gate and baggage claim, enlargement of express cargo facilities, electrical refurbishments, departure lounge refurbishments and underground station and other terminal improvements all of which have been completed. In July 2013, a new commercial area was inaugurated in the Terminal 1 air side area with 20 new stores and spacious naturally lighted internal circulation areas. In July 2015, a significantly larger food court was introduced, catering to more tastes and delicacies. In January 2019, Portugal's government unveiled a €1.1 billion plan to expand the airport. Although the airport is at capacity, the expansion faces opposition due to impacts on pollution and noise. Construction began in December 2024 on the expansion of Terminal 1, with 10 new jet bridges and more space for apron. The expansion project is expected to be completed by 2027 and increase the airport's capacity to receive up to 50 million passengers per year.