How do sailplanes (gliders) stay aloft?
Gliders are usually towed to altitude by a motorized airplane and then use rising air from natural weather phenomenas such as thermals, mountain lee waves or ridge lift to stay aloft.
Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request.
### Instruction: How do sailplanes (gliders) stay aloft?
### Input: 
### Response: Gliders are usually towed to altitude by a motorized airplane and then use rising air from natural weather phenomenas such as thermals, mountain lee waves or ridge lift to stay aloft.