To date, the U.S. Air Force has purchased 114 Predator A UAVs, with the CIA getting another dozen. So far, 37 percent of those Predators have been lost in action, mostly to accidents. Having a pilot on board does much to reduce accidents, although the air force is improving UAV operator training, and the flight control software, and the accident rate is going down. Each Predator A lost costs $4.5 million. The air force has ordered another 144 Predators, and some of these will be the larger Predator B. This version can stay in the air for about 24 hours (compared to 40 hours for the A model), and, most importantly, carries 1.7 tons of munitions. This can include Hellfire missiles, and 250 or 500 pound smart bombs. Typically, the Predator B will go into action carrying 16 Hellfire missiles. The Predator B is meant to be a hunter-killer UAV. It will go into action looking for targets it can immediately attack. 

The Predator B prototypes have been flying since 2001, and have performed well. But the air force does not want to rush it into service, and will continue testing for another 12-18 months. Each Predator B costs $7 million. The army particularly likes the Predators because they have persistence (the ability to stay over a battlefield for hours on end.) The air force is reluctant to keep shifts of manned aircraft over a battlefield for that long, if only because its so expensive (about $4,000 an hour, on average, for most fighter bombers, about ten times the hourly cost of flying a Predator.) There are also not enough manned warplanes to provide that kind of persistence. The air force is also developing new flight control software for Predator, that will allow one pilot to control four Predators, while each of those four UAVs will have one sensor operator. Current software requires one pilot and two sensor operators per Predator in flight. The Predator spend the vast majority of their time just watching the ground below.

In response to troop demand for UAVs, the army has sent hundreds of smaller UAVs to Iraq and Afghanistan, for reconnaissance, and is rushing a GPS guided 155mm artillery shell (Excalibur) into service by next Spring, to take advantage of targets spotted by all these UAVs.. The army doesnt want to be dependent on the air force for persistence, while the air force is not looking forward to replacing its manned fighter-bombers with armed UAVs. However, thats where the air force is going. The Predator B will have the same weapons load of an F-16, although it will fly much slower (max, about 400 kilometers an hour.) But for ground attack, slower speed is an asset. The Predator B will be more reliable (have a lower accident rate) and possess better sensors than the Predator A.