Note: While many weapons systems can be considered UAVs, this node will be primarily about UAV's designed to be reused, not guidable missiles or bombs
Unmanned Aerial Vehicles have been experimented with as far back as American civil war, in the form of balloons with attached payloads (usually explosives or propaganda leaflets). The most famous balloon campaign was launched by the Japanese in WWII in retaliation of the Doolittle Raid on the Japanese mainland. Around 9,000 paper and rubberized silk balloons were constructed and launched from the Japanese island Honshu. Of these, around 1,000 were carried by high altitude winds to United States. The balloons were equipped with incendiary (intended to cause forest fires) and anti-personnel explosives. On May 5, 1945, six picnickers were killed in Oregon when they attempted to recover a balloon bomb, which exploded. These were the only known casualties on United States soil during WWII.
Vietnam
The Vietnam War witnessed the extremely successful use of UAVs as surveillance devices, which remains their primary purpose today. The Firebee AQM-34 drone was a modified Q-2C Firebee, a drone developed for target practice. Engineers made modifications to reduce the drone's radar signature, through the attachment of radar absorbent blankets and a few coats of newly developed radar absorbent paint. The drone could be fitted with a variety of surveillance devices, ranging from a simple TV camera to Doppler radar. Models were also adapted to drop propaganda leaflets over North Vietnamese territory or jam enemy radar. The Firebee drones proved to be extremely adaptable and reliable, 83% of the drones successfully returned from missions. The drones were operated by the 556th Recon Squadron (which was responsible for other high-tech military experiments, including project IglooWhite). Drones were deployed from the DC-130 control aircraft while in flight. The drones would then execute pre-programmed missions, although one of the two operators onboard the DC-130 could override and take manual control. After completing its mission, a drone would fly to a extraction point, release a parachute, and later be picked up via helicopter. The Firebee drones were very successful in their stealth reconnaissance role, and they flew more than 34,000 operational surveillance missions over Southeast Asia from October 1964 to April 1975.
Operator overrides were used several times during the war to creatively turn the unarmed drone into a combat aircraft. The 1st "kill" by a drone occurred in May of 1970. After a recon mission over Hanoi a Firebee drone was intercepted by a North Vietnamese MiG-21 en route to its extraction point in the Gulf of Tonkin. The MiG-21 fired two air-to-air missiles, both of which malfunctioned. The MiG continued pursuit and attempted to down the drone by clipping its wing. Before the drone could be physically knocked out of the sky, it deployed its parachute and landed safely into the waters below. The MiG pilot, however, had forgotten to monitor his fuel gauge and he was forced to eject when his plane ran out of fuel. The drone was recovered, and flew several uneventful missions until the 9th of March, 1971. During a recon flyover, the drone was intercepted by two MiGs. After extensive evasive maneuvers by the drone, a MiG pilot finally got a lock with an air-to-air missile, and scored a direct hit . . . on his wingman. Several weeks later the very same unmanned and unnamed drone was targeted by ground based anti-aircraft fire which it escaped, unlike the MiG pursing it. During the remainder of its career it reportedly scored 2 more kills. Should aforementioned tale of courage and heroics by an unmanned drone and operator be true, and not just a war legend, the drone could be classified as the 1st American fighter ace in the Vietnam War.
Operation Desert Storm
High Tech UAVs made possible with advances in computer and communications technologies appointed the 1991 Gulf War with the very appropriate designation of "Modern War."
Pioneer
Used by American forces, the Pioneer drone is an Israeli designed and American built UAV. After hearing of Israeli success with the UAV, the US Navy procured platform with the intention of using it for imagery intelligence (IMINT), to act as a spotter for sea-based artillery. It has a 17 ft wingspan, and is 14 ft long. It is powered by a 26 horsepower snowmobile engine and has a range of approximately 100 miles. It is launched via catapult from a ground location or ship. Unlike the Firebee, the Pioneer drone is guided via remote control by an operator in real-time and is equipped with a high-resolution camera which takes detailed pictures at a standard cruising height of 2,000 ft. The Pioneer was used very successfully by the US Navy in Operation Desert Storm in its IMINT role. The drone determined coordinates of Iraqi fortifications on the Kuwaiti coastline, which were then shelled by Navy artillery. The Pioneer was used by ground forces to survey large expanses of desert and terrain (Tomahawk missiles use terrain recognition for guidance, and areas must be mapped before the cruise missiles can be deployed.) and to determine targeting coordinates of enemy forces. Iraqi troops began to associate the high-pitched engine whine of the Pioneer with impending doom from above, courtesy of Navy artillery or the Air Force. After Faylaka Island was shelled by the USS Missouri, with the aid of Pioneer provided targeting coordinates, high command decided to fly a Pioneer low over the island. The remaining Iraqis scrambled to find and franticly wave anything and everything white, prompting the Navy operator to ask, "Sir, they want to surrender, what should I do with them?" It was the first time man surrendered to machine
War on Terror
The recent war in Afghanistan and Gulf War II have been the most successful times for UAVs; the two newest (declassified) American models are the Predator and the Global Hawk. The Predator has a range of about 460 miles and can remain in flight for up to 16 hours. A drone currently costs 3.2 million dollars. A CIA modified version carries a single hellfire anti-armor rocket. A Predator was used to destroy a car containing six suspected al-Qaeda members in a Yemen desert. Qaed Senyan al-Harthi, a former bin Laden bodyguard who was believed to have played a major role in the October 2000 attack on the destroyer Cole that killed 17 sailors was killed in the attack. A CIA drone was also used to attack a suspected al-Qaeda convoy in Afghanistan, although civilians in the area claim the convoy was civilian, not al-Qaeda. Hellfire-armed Predator drones were used to destroy Iraqi mobile radar sites during Gulf War II. Due to its low-flying nature, the Predator is extremely susceptible to both anti-aircraft and small arms fire. The Predator is also a very fragile aircraft, and cannot be flown in certain weather conditions. Since it's release into service in 1994, around 30 of the 70 drones in the Predator fleet have been lost, prompting many to question the program's cost effectiveness.
The Global Hawk is a high altitude (around 65,000 ft) recon drone which is programmed to fly automatically without human intervention for spans of up to 40 hours. It was used extensively during the Afghanistan war, where drones returned 15,000 high resolution images and logged 1,000 combat hours. It is very likely the drones were used in Gulf War II, but any such information is currently classified.
http://www.wpafb.af.mil/museum/history/wwii/jbb.htm
http://www.acig.org/artman/publish/article_14.shtml
http://www.pbs.org/wgbh/nova/spiesfly/uavs.html
http://www.pbs.org/wgbh/pages/frontline/gulf/weapons/drones.html
http://www.cnn.com/2002/US/11/04/predator.background/index.html
http://www.cnn.com/2002/WORLD/meast/11/05/yemen.blast/index.html
http://www.cnn.com/2003/US/01/02/sproject.irq.predator.losses/index.html