What is the main advantage of unmanned vehicles?

Iran is making a new type of military weapon. It’s a long-range pilotless airplane, an unmanned aerial vehicle. They’re pretty common in modern combat. The U.S. uses something called a Predator pilotless airplane. (29) And American officials say the unmanned vehicles help cut down risk for troops because no one actually has to be on board piloting it. Iran started producing its unmanned airplanes back in February. The first ones were unveiled yesterday. (30)Iranian officials say the planes have a range of about 620 miles and can carry different types of bombs and missiles to hit ground targets. They claim that the goal of the new vehicles is to prevent aggression against their country. Meanwhile, Iran has started fueling a new nuclear energy plant. It says the plant will help make electricity. But other countries, including the United States, think Iran may try to make nuclear weapons.