Aircraft spotting, or plane spotting, is a hobby of tracking the movement of aircraft, which is often accomplished by photography. Besides monitoring aircraft, plane spotting enthusiasts (who are usually called plane spotters) also record information regarding airports, air traffic control communications and airline routes. History and evolution Aviation enthusiasts have been watching airplanes and other aircraft ever since they were invented. However, as a hobby (distinct from active/wartime work), plane spotting did not appear until the second half of the 20th century. During World War II and the subsequent Cold War some countries encouraged their citizens to become "plane spotters" in an "observation corps" or similar public body for reasons of public security. Britain had the Royal Observer Corps which operated between 1925 and 1995. A journal called The Aeroplane Spotter was published in January 1940. The publication included a glossary that was refined in 2010 and published online. The development of technology and global resources enabled a revolution in spotting. Point and shoot cameras, DSLRs & walkie talkies significantly changed the hobby. With the help of the internet, websites such as FlightAware and Flightradar24 have made it possible for spotters to track and locate specific aircraft from all across the world. Websites specifically for aircraft, such as airliners.net, and social networking services, such as Twitter, Facebook and Instagram, allow spotters to record their sightings and upload their shots or see pictures of aircraft spotted by other people from all over the world. People can upload videos to YouTube, including inflight videos. Techniques When spotting aircraft, observers generally notice the key attributes of an aircraft, such as a distinctive noise from its engine, the number of vapour trails it is leaving or its callsign. Observers assess the size of the aircraft and the number, type and position of its engines. Another distinctive attribute is the position of wings relative to the fuselage and the degree to which they are swept rearwards. The wings may be above the fuselage, below it, or fixed at midpoint. The number of wings indicates whether it is a monoplane, biplane or triplane. The position of the tailplane relative to the fin(s) and the shape of the fin are other attributes. The configuration of the landing gear can be distinctive, as well as the size and shape of the cockpit and passenger windows along with the layout of emergency exits and doors. Other features include the