In recent years, the United States has increased its economic sanctions against Iran, which has led to a serious collapse of the Iranian economy and a lot of grievances between the two sides. Of course, Iran and the United States have a lot of grievances in history, mainly because Iran's religious forces overthrew the Pahlavi dynasty, and the hostage incident at the American embassy also occurred at that time, which also led to frequent frictions or conflicts between Iran and the United States.
Of course, the United States will never strike Iran easily. Once a military strike is carried out against Iran, it is likely to be strongly retaliated by Iran, because Iran's ballistic missile technology is very mature, which also makes the United States have to think twice before attacking by force. Moreover, the United States is now unable to launch a large-scale local war. At present, the domestic economy of the United States is very weak and it is unable to wage local wars.
So we can see that Iran can always shoot down American drones, mainly because Iran's ballistic missile technology is very mature, so owning this technology will also seriously threaten the interests of the United States.