Ion Tiger UAV by Naval Research Laboratory, Washington, D.C.
Habitat: European airfields, potentially, from which it could reach the Middle East, once the Navy perfects the fuel-cell technology inside. It could fly as low as 1,000 feet without being heard on the ground, or as high as 14,000 feet.
Behavior: Its ability to stay aloft for 24 hours allows the Ion Tiger to encroach on the terrain of much bigger birds, such as the Predator, and its small size lets it get closer to a target to shoot footage with its lighter, cheaper camera.
Notable Feature: Its carbon-wrapped aluminum hydrogen tanks weigh only about nine pounds each, which helps this UAV stay airborne longer.