The Tupolev Tu-134 (NATO codename: Crusty) is a Soviet twin-engined airliner, similar to the American Douglas DC-9. One of the most widely used aircraft in the former Warsaw Pact countries, the number in active service is decreasing because of noise restrictions. The model has seen long-term service with some 42 countries throughout Europe, Southeast Asia, the Middle East, Africa and Latin America, with some European airlines making very intense use of the 134 (as many as 12 takeoffs & landings per plane daily). In addition to regular passenger service, it has also been used in various airforce, army and navy support roles; for pilot and navigator training; and for aviation research and test projects. In recent years, a number of planes have been converted for use as VIP transportation. A total of 796 Tu-134s were built.