Every war brings its signature weapon. In World War I, it was the fighter plane; in WWII, the atomic bomb. The Cold War produced missiles capable of traveling halfway around the world in under an hour. And in the war on terror, the tip of the spear is undoubtedly the unmanned aerial vehicle, or UAV.

Though popularly dubbed “drones,” the current generation of unmanned aircraft don’t operate autonomously during flight; they are controlled by military personnel on the ground. In the case of the Air Force, Predator and Reaper aircraft flying over Afghanistan are operated by pilots located just outside of Las Vegas.

Once regarded as a niche tool, UAVs have emerged as one of the most high-profile weapons in current military operations. In Iraq, an aviation battalion that uses manned and unmanned aircraft, called Task Force ODIN (an acronym for Observe, Detect, Identify and Neutralize) has been credited with capturing or killing thousands of insurgents responsible for planting roadside bombs. The Pentagon is hoping ODIN will eventually see the same success in Afghanistan.

Drones also are expanding internationally. In 2008, Russia shot down a Georgian drone that was flying over the breakaway region of Abkhazia. Although Russia soundly defeated Georgia in a war that followed several months later, Russia realized its own drones weren’t nearly as advanced as the ones owned by Georgia; now, Russia is buying unmanned aircraft from Israel, the same country that supplied the drones to Georgia in the first place.

But unmanned aircraft, though growing in number and uses, are hardly perfect. In Afghanistan, insurgents using cheap commercial software were famously able to hack into the video feed coming from US military drones. Nor is drone technology limited to traditional militaries. The military wing of the Lebanon-based Hezbollah bragged about flying its Mirsad-1 UAV into Israeli airspace. In the US, military concerns that terrorists could obtain small drones and use them to attack across borders has even prompted a secretive effort called “Black Dart,” which looks at ways to detect and destroy UAVs. One method involves frying the electronics with targeted microwave energy.

On the more futuristic end of the spectrum, researchers sponsored by the Defense Department are looking at everything from drones that mimic insects (one US Air Force promotional video even shows an insect-sized drone on an assassination mission), to actual living insects implanted with microelectronics that control their flight. Such cyborg insects, according to the Pentagon research agency funding the work, could act as tiny spies, carrying microphones or sensors to a specific target. Though still far away from the battlefield, scientists have already been able to remote control a beetle implanted with a neural stimulating device.

Cheaper than manned aircraft (though, at roughly $10 million a drone, not as cheap as the Pentagon would like), UAVs can be sent into places deemed too unsafe for manned aircraft. The Air Force is already looking ahead at options for a next-generation drones, faster and stealthier than the current generation of Reaper and Predator aircraft.

For instance, a new drone that looks like a miniature stealth fighter, nicknamed the “Beast of Kandahar” was spotted on a US base in Afghanistan. The very public outing prompted the Air Force to confirm that it did indeed have a new, previously unacknowledged, unmanned aircraft in its arsenal. Officially called the RQ-170 Sentinel, the spy aircraft may have been operating out of Afghanistan for some two years.

The radar evading drone, built by Lockheed Martin’s secretive Skunk Works division, is a tail-less aircraft with sensors integrated into the wings and operated by the Air Force’s 30th Reconnaissance Squadron based at the Tonopah Test Range in Nevada.

Its mission? Unclear, but since the Taliban don’t possess radar, aerospace expert experts speculate the aircraft could be used for spying on the world’s next international flashpoint: Iran’s nuclear program.

Sharon Weinberger is a national security reporter and contributor to AOL News/Sphere.