what's the maximum distance they have flown?
Up to 1,000 km
Gliding
Tasks of up to 1,000 km have been set and average speeds of 120 km/h are not unusual.
how long do gliders stay in the air They can stay airborne for several hours. what is gliding? It is a recreational activity and competitive air sport in which pilots fly unpowered aircraft known as gliders or sailplanes using naturally occurring currents of rising air in the atmosphere to remain airborne. who created the first glider? The Germans when? In  the 1920s and 1930s how do they fly? Through air that is ascending as fast or faster than the glider itself is descending, thus gaining potential energy. what's the fastest they can go? UNANSWERABLE so you mean they use lift to fly? Yes, ridge lift, wave lift etc. how are they launched? Different methods, namely aerotowing, winch launching, bungee launch etc.
wiki:14186551
Gliding [SEP] Cross-country
As the performance of gliders improved in the 1960s, the concept of flying as far away as possible became unpopular with the crews who had to retrieve the gliders. Pilots now usually plan to fly around a course (called a "task") via turn-points, returning to the starting point. In addition to just trying to fly further, glider pilots also race each other in competitions. The winner is the fastest, or, if the weather conditions are poor, the furthest round the course. Tasks of up to 1,000 km have been set and average speeds of 120 km/h are not unusual.