Aircraft spotting is a hobby involving the pursuit of different aircraft, gliders, powered aircraft, large balloons, airships, helicopters, microlights and, less probably, drones and hovercraft. The fun is in the identification of aircraft - their manufacturer, type and perhaps serial number - often in difficult circumstances (e.g. when at some distance or when obstructed by others or in darkness). Ancillary activities might include listening-in to air traffic transmissions (where that is legal), liaising with other "spotters" to clear up uncertainties as to what aircraft have been seen at specific times and/or in particular places, and the drawing, painting, filming, tape-recording or photographing of aircraft.
The more enthusiastic hobbyists might travel great distances in order to see particularly unusual aircraft, or even the remains of aircraft withdrawn from use. Some such "wrecks and relics" may eventually be placed in the care of museums - or perhaps be canibalised in order to repair a similar aircraft already preserved. Some spotters may go on to work in the aviation industry or air traffic control service. During the Cold war some countries encouraged their populations to become "plane spotters" in an "observation corps" or similar public body for reasons of public security. Some spotters are quite competitive and may get a thrill from seeing, in due course, all the planes of a particular type ever built (or extant at that date). Spotters are generally well-aware of the hazards facing aviators and will stay alert when near active aerodromes, taking care not to interfere with aircraft or cause anxiety to their owners or users. Many airfields in Australasia, Europe and north America recognise the public's interest in aviation as something to be encouraged and provide viewing areas in safe locations. Many organised airshows draw large crowds and some raise funds for charitable causes such as museums, organisations restoring historic planes or bodies that assist injured aircrew or the dependents of Armed Forces' personnel. Some shows have a more commercial motive, and some aircraft photographers can make a profit from their onetime hobby. The World Wide Web has provided a new outlet for some of their photographs and assists all spotters in letting each other know what is flying where.
Aircraft spotting is not, however, recognised as a legitimate hobby in Greece where the authorities remain concerned about note-taking and photography on or near airfields. This attitude resulted in an international dispute late in 2001 between the Netherlands, United Kingdom and Greece following the arrest of 2 Dutch and 12 British plane spotters travelling together, who had been invited to Kalamata's Open Day, initially on spying charges. After they had spent over a month in prison, three judges sitting as a Panel in Kalamata reduced the charge on 12th December to "accessing national secrets" and on payment of bail the 14 spotters were freed. Trials can be expected during 2002.