However, in any significant wind the round shape is aerodynamically unstable and will bob about, risking damage or the balloon breaking free.
[2][3] A hybrid tethered balloon or kytoon is shaped to provide aerodynamic lift similar to a kite, as well as to reduce drag.
Tethered balloons are used for lifting cameras, radio antennas, electro-optical sensors, radio-relay equipment and advertising banners – often for long durations.
The United States Geological Survey uses tethered balloons to carry equipment to places where conventional aircraft cannot go, such as above an erupting volcano.
Tethered balloons are ideal as they can easily remain more or less in one place, are less likely to be damaged by volcanic ash, and are less expensive to operate than a helicopter.
The advantage of tethered balloons is that great antenna heights are easily attainable and they are significantly cheaper than erecting a temporary mast.
The US Drug Enforcement Administration has contracted with Lockheed Martin to operate a series of radar-equipped tethered balloons to detect low-flying aircraft attempting to enter the United States.