Lasers, nets, and electronic warfare all come to mind.
Key point: Small drones are cheap and hard to destroy. Here is how the Army hopes it can defend itself against them.
Swarms of enemy drones approaching a forward operating base or groups of dismounted soldiers present a unique and increasingly challenging threat. Enemy drones can blanket areas with surveillance, test enemy defenses, jam communications and even themselves become explosives to attack targets.
This first appeared earlier and is being reposted due to reader interest.
The variety of uses of small drones, and the guidance systems which direct them, can be very difficult to defend against, a reality inspiring the current Air Force effort to solicit new ideas on ways to destroy them. The Air Force recently released a Request for Information (RFI) to industry, asking for new innovations able to counter small enemy drones.