Long distances are now flown using any of the main sources of rising air: ridge lift, thermals and lee waves.

Although in most countries the standards of safety of the pilots and the aircraft are the responsibility of governmental bodies, the clubs and sometimes national gliding associations often have delegated authority.

The development of heavier-than-air flight in the half century between Sir George Cayley's coachman in 1853 and the Wright brothers in 1903 mainly involved gliders (see History of aviation).

However, the sport of gliding only emerged after the First World War, as a result of the Treaty of Versailles,[6] which imposed severe restrictions on the manufacture and use of single-seat powered aircraft in Germany's Weimar Republic.

In 1931, Gunther Grönhoff flew 272 kilometres (169 mi) on the front of a storm from Munich to Kadaň (Kaaden in German) in Western Czechoslovakia, farther than had been thought possible.

[9]: 107  During the war, the sport of gliding in Europe was largely suspended, though several German fighter aces in the conflict, including Erich Hartmann, began their flight training in gliders.

)[9]: 172  The re-introduction of air sports such as gliding to the Olympics has occasionally been proposed by the world governing body, the Fédération Aéronautique Internationale (FAI), but has been rejected on the grounds of lack of public interest.

[6][24]: 135  In places where a steady wind blows, a ridge may allow virtually unlimited time aloft, although records for duration are no longer recognized because of the danger of exhaustion.

[6] Wave lift was used to set the current altitude record (to be ratified) of 23,202 metres (76,122 ft) on 2 September 2018 over El Calafate, Argentina.

[18] The current world distance record of 3,008 kilometres (1,869 mi) by Klaus Ohlmann (set on 21 January 2003)[26] was also flown using mountain waves in South America.

The height gained from a winch is usually less than that from an aerotow, so pilots need to find a source of lift soon after releasing from the cable, or else the flight will be short.

After gently taking up slack in the cable, the driver accelerates hard and as a result the glider rises rapidly to about 400 metres (1,300 ft), especially if there is a good headwind and a runway of 1.5 kilometres (0.93 mi) or more.

A good gliding performance combined with regular sources of rising air enables modern gliders to fly long distances at high speeds.

[47] Furthermore, gliders are not visible to the spectators for long periods during each day's contest and the scoring is complex, so traditional gliding competitions are difficult to televise.

There is a decentralized Internet-based competition called the Online Contest, in which pilots upload their GPS data files and are automatically scored based on distance flown.

However at higher speeds the glider also sinks faster, requiring the pilot to spend more time circling to regain the altitude.

[22]: 56 On cross-country flights on days when strong lift is forecast, pilots fly with water ballast stored in tanks or bags in the wings and fin.

The fin tank is used to reduce trim drag by optimizing the center of gravity, which typically would shift forward if water is stored only in the wings ahead of the spar.

[22]: 63  If lift is weaker than expected, or if an off-field landing is imminent, the pilot can jettison the water ballast by opening the dump valves.

This 'dolphining' technique can result in high average speeds because the height lost can be minimised until particularly strong lift is encountered when circling would be most effective.

A pilot who has earned the Gold badge has achieved an altitude gain of 3,000 metres (9,843 ft), made a flight of five-hours duration, and flown cross-country for a straight-line distance of at least 300 kilometres (186 mi).

Unpowered gliders are lighter and, as they do not need a safety margin for starting the engine, they can safely thermal at lower altitudes in weaker conditions.

Although training and safe procedures are central to the ethos of the sport, a few fatal accidents occur every year, almost all caused by pilot error.

In several European countries and Australia, the FLARM warning system is used to help avoid mid-air collisions between gliders.

In addition to solo flying, further flights are made with an instructor until the student is capable of taking a glider cross-country and of handling more difficult weather.

Cross-country flights are allowed when they have sufficient experience to find sources of lift away from their home airfield, to navigate, and to select and land in a field if necessary.

In most countries pilots must take a written examination on the regulations, navigation, use of the radio, weather, principles of flight and human factors.

Because most gliders are designed to the same specifications of safety, the upper weight limit for a pilot, after allowing for a parachute, is usually 103 kilograms (227 lb).

Although all three sports rely on rising air, there are significant differences which are listed in detail in a comparison of sailplanes, hang gliders, and paragliders.

The main difference is that both hang gliders and paragliders are simpler, less sophisticated and cheaper aircraft that use the pilot's feet as the undercarriage.