Most of the active drones are deployed from military installations, enforcement agencies and border patrol teams, according to the Federal Aviation Authority. But, astonishingly, 19 universities and colleges are also registered as owners of what are officially known as unmanned aerial vehicles.
It is thought that many of institutions, which include Cornell, the University of Colorado, Georgia Tech, and Eastern Gateway Community College, are developing drone technology.
However, the FAA is yet to reveal what kinds of drones might be based at any of these locations. The agency says it will release this data later.
While few would object to vast open areas being monitored for wildfires, there are fears of privacy violations if drones are used to spy over cities.
Other drones – likely to be operated only by the armed forces – might include the MQ-9 Reaper and the MQ-1 Predator, which was used to kill American Al Qaeda boss Anwar al-Awlaki in Yemen last September.
The FAA has confirmed that there were about 300 active COAs and that the agency has issued about 700-750 authorizations since the program began in 2006. But this information does not reveal how many are owned, for example, by Miami Dade Police Department.
While the use of drones in the U.S. is little known, American operations overseas have been well documented. As well as high-profile terrorists, campaigners claim hundreds of innocent civilians have been killed in the border regions of Pakistan, where they are most active.