The US Navy is developing unmanned aerial vehicles (UAVs), or drones, that can be launched from a cannon and "swarm" in a co-ordinated attack.
The drones will be able to fly autonomously and "overwhelm an adversary", the US Office of Naval Research said of its Low-cost UAV Swarming Technology (Locust) programme.
Wings unfold once the drones are in the air and then they can fly in formation.
The US Navy plans to demonstrate the launch of 30 Locust drones in 2016.
As the drones and the launcher are relatively compact, the Locust system can be deployed from ships, aircraft or land vehicles, the ONR said.
Missions can be pre-programmed, but there "will always be a human monitoring the mission", it added.
"This level of autonomous swarming flight has never been done before," said Lee Mastroianni, ONR programme manager.
"UAVs that are expendable and reconfigurable will free manned aircraft and traditional weapon systems to do more, and essentially multiply combat power at decreased risk to the warfighter."
US use of military drones has attracted criticism from human rights groups, who say that despite their highly targeted nature, innocent non-combatants are often killed in the process.
The prospect of autonomous swarms of drones carrying out pre-programmed military missions is only likely to increase such concerns.