Balloons
Balloons drift with the wind, though normally the pilot can control the altitude either by heating the air or by releasing ballast, giving some directional control (since the wind direction changes with altitude). A tethered wing-shaped balloon has been tested which has greater directional control. Today, the majority of the use of manned balloons is recreational, whereas unmanned balloons are widely used for meteorological measurement.
Read more about this topic: Unpowered Aircraft
Famous quotes containing the word balloons:
“Canaries in the morning, orchestras
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—Wallace Stevens (1879–1955)