What is the most energy efficient aircraft?

I just heard that the bird abatrost can fly in the sea for thousands of
miles
without feeding since they can employee the wind efficiently in order to
get energy from the air and it's gliding technique is also most efficient
among
all the birds. Is this true?

Is it likely we can learn these tricks and design some UAVs that can fly
thousands of miles and survillience the seashore?

>I just heard that the bird abatrost can fly in the sea for thousands of

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"oðin" <oð[Only registered users see links. ]> wrote in message
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efficient

The technical problem in UAV surveillance is 2-way telemetry - how do you
transmit live multi-channel poly-chromatic video, control remotely, and
maintain a long useful range?

The tactical problem - the longer it is airborne, the more time it spends as
a possible target.

The budgetary problem - the longer its range, the more expensive it will be.

The FAS has a page on UAVs that is most informative:
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The Global Hawk (range 3000 nautical miles, loiter capability 24 hours,
altitude over 60,000 feet) has been around for a little while (1999):
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The current altitude record holder (80,300 ft) for propeller-driven aircraft
is a UAV:
the Pathfinder-Plus (NASA Dryden)
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It is solar powered; endurance is limited by daylight to 14-15 hours
(including 2-3 hour battery backup. Airspeed is approx. 17-20 mph. Range is
therefore limited.

A current development in field UAVs is toward having small (8.5 pounds),
short-range, man-portable units that can be launched, maintained, and
retrieved in the field by a two-man team in a high-mobility vehicle (e.g. a
HMMV):
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Tom Davidson
Richmond, VA