American researchers took control of a flying drone by hacking into its GPS system - acting on a $1,000 (£640) dare from the US Department of Homeland Security (DHS).
A University of Texas at Austin team used "spoofing" - a technique where the drone mistakes the signal from hackers for the one sent from GPS satellites.
The same method may have been used to bring down a US drone in Iran in 2011.
Analysts say that the demo shows the potential danger of using drones.
Drones are unmanned aircraft, often controlled from a hub located thousands of kilometres away.
They are mostly used by the military in conflict zones such as Afghanistan...