Lines in 1952. She won the Blue Riband on her maiden voyage in that year and held it until Richard Branson won it back in 1986 with Virgin Atlantic Challenger II. One year later, in 1953, Italy completed the , which later sank in 1956 after a collision with . Before the Second World War, aircraft had not posed a significant economic threat to ocean liners. Most pre-war aircraft were noisy, vulnerable to bad weather, and/or incapable of the range needed for transoceanic flights; all were expensive and had a small passenger capacity. The war accelerated development of large, long-ranged aircraft. Four-engined bombers, such as the Avro Lancaster and Boeing B-29 Superfortress, with their range and massive carrying capacity, were natural prototypes for post-war next-generation airliners. Jet engine technology also accelerated due to wartime development of jet aircraft. In 1953, the De Havilland Comet became the first commercial jet airliner; the Sud Aviation Caravelle, Boeing 707 and Douglas DC-8 followed, and much long-distance travel was done by air. The Italian Line's and , launched in 1962 and 1963, were two of the last ocean liners to be built primarily for liner service across the North Atlantic. Cunard's transatlantic liner, , was also used as a cruise ship. By the early 1960s, 95% of passenger traffic across the Atlantic was by aircraft. Thus the reign of the ocean liners came to an end. By the early 1970s, many passenger ships continued their service in cruising. In 1982, during the Falklands War, three active or former liners were requisitioned for war service by the British Government. The liners Queen Elizabeth 2 and , were requisitioned from Cunard and P&O to serve as troopships, carrying British Army personnel to Ascension Island and the Falkland Islands to recover the Falklands from the invading Argentine forces. The P&O educational cruise ship and former British India Steam Navigation Company liner was requisitioned as a hospital ship, and served after the war as a troopship until the RAF Mount Pleasant station was built at Stanley, which could handle trooping flights. 21st century By the first decade of the 21st century, only a few former ocean liners were still in existence; some, like , were sailing as cruise ships while others, like , were preserved as museums, or laid up at pier side like SS United States. After the retirement of Queen Elizabeth 2 in 2008, the only