Military and police forces across the world are investing in unmanned aircraft to spot threats and hunt down targets.
These spies in the sky, small craft that operate under remote control or autonomously navigate waypoints, come in all sizes - from silent planes no bigger than a bird to substantial craft packed with surveillance and measurement equipment or munitions.
A variety of drones were on display at the UK's Farnborough International Airshow, and TechRepublic went along to check them out.
The distinctive shape of this Predator C Avenger drone is designed to make it harder for electronic systems to spot by reducing the craft's electromagnetic and thermal emissions.
Designed to stay in the air for a maximum of 20 hours, the drone operates at an altitude of 53,000 feet with a cruising speed of 400 knots - 460 mph.
The Avenger's manufacturer, General Atomics, says the craft can perform wide-area surveillance and time-sensitive strike missions over land or sea, as well as other military roles.
The drone's payload enables it to carry multiple sensors, while its internal weapons bay can house 3,000lb of precision munitions.
Photo: Nick Heath/TechRepublic