ALTHOUGH undeniably graceful, gliding has until now
been suitable only for pleasure flights. But this is
changing, as researchers exploit wind power to enhance
the capabilities of unmanned aircraft, especially
small drones. Soon, these gliders will be able to
stay aloft for weeks. They will thus be able to act
as communication relays, keep a persistent eye on
the ground below and even track marine animals
thousands of kilometres across the ocean.

One such glider, the hand-launched Tactical Long
Endurance Unmanned Aerial System...
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The full article is at
http://www.economist.com/blogs/babba...manned-gliders