In May 2025, during Operation Sindoor, Pakistan sent wave after wave of drones across India’s western border. Intrusions were attempted at 36 locations between Leh and Sir Creek. The Director General of Army Air Defence later put the four-day total at between 800 and 1,000 drones. Many flew low, he said, to confuse gunners and saturate radars. Most were brought down by guns.

The public account of those nights was about interception: how many came and how many fell. Underneath it sat a different question, one every air-defence planner now has to answer. What did each interception cost, and could the defence have kept paying that price if the waves had continued for weeks rather than days?

That question rarely makes headlines. It is the invisible balance of drone warfare, and it increasingly decides who can sustain a fight.

Analysts call it the cost-exchange ratio: what a defender spends to stop each thing an attacker sends. For most of the history of air defence, the ratio mattered less, because the threats were expensive too. A fighter jet or a cruise missile justified an expensive interceptor.

Cheap drones changed that. In the Red Sea, US Navy ships used Standard Missile-2 interceptors, at about $2 million each, against Houthi drones estimated to cost a few thousand dollars, according to CSIS. Russia’s Shahed-type attack drones are estimated at around $35,000 each, while a single Patriot interceptor costs millions. Commenting on the conflict with Iran this year, retired US General David Petraeus called this “not a good exchange against a drone that costs at most $30,000.”

The attacker’s logic is simple. A drone does not have to reach its target to succeed. If it forces the defender to spend far more than it cost, or to draw down a stockpile that cannot be replaced quickly, it has already done part of its job. Send enough of them, and the attacker can try to exhaust the defence before the decisive strike arrives.

The obvious response is to make the interceptor cheaper, and the industry is moving quickly. Ukraine’s Sting interceptor drone costs roughly $2,100 to $2,500, according to Military Times, and its maker says it had downed around 3,900 drones by early 2026. Guns, lasers, electronic attack and low-cost missiles are all in development or in service. India’s own experience points the same way: the upgraded L-70 guns that did much of the work during Operation Sindoor cost far less per shot than a missile.

But cost-exchange logic has limits, and treating it as the whole story creates a risk of its own. An analysis from the Modern War Institute at West Point argues that the right comparison is not between an interceptor and the drone it destroys, but between the interceptor and the loss it prevents. There is no cheap answer to a ballistic missile. A defence optimised only for cost per shot can end up without the layers that stop the threats that matter most.

The balance, then, is not cheap against expensive. It has two sides. Scarce, expensive interceptors should be kept for threats only they can stop, and cheap threats should meet cheap, proportionate responses. Err in one direction and a missile is spent on a $30,000 drone. Err in the other and something that needed a missile gets through.

Whether a defence lands on the right side of that balance depends less on what it owns than on how it chooses. Every engagement follows a sequence. A sensor detects something, the contact is tracked and classified, someone decides how to respond, and an effector is cued in time to act.

A cheap interceptor only helps if it is in range, available and cued early enough. A low-cost gun only helps if the radar track reaches it with enough warning. When detection and response sit on separate systems, from different vendors and with no shared picture, operators work with whatever is in front of them. Under saturation, that is often the response that can act fastest, which is not always the most proportionate one.

For the choice to be a good one, three things have to be visible at once: what the threat is likely to be, which responses are available across neighbouring units, and what each would cost, including what is left in the stockpile. This is a coordination problem, not a procurement problem. Adding another layer of hardware does not solve it, because every new layer is one more option someone has to choose between, quickly and under pressure.

A mosaic illustration of an operator in headphones facing a wall of screens showing radar tracks and drone feeds

What this means for India

India is assembling the pieces. In August 2026, the Army issued a tender for an AI-enabled high-speed interceptor UAV for counter-drone operations. In October, the Ministry of Defence signed a contract worth about Rs 770 crore with BEL for Improved Low-Level Lightweight Radars to counter drone threats. The Air Force has explored low-cost interceptor missiles, and upgraded L-70 guns now carry radar cueing, electro-optical tracking and automated fire control. Above all of this, Mission Sudarshan Chakra aims to build a layered national air-defence shield by 2035.

Each of these adds a layer at a different price point, which is exactly what a sustainable cost-exchange needs. The open question is whether those layers will work as one system. Akashteer showed during Operation Sindoor what a shared air picture can do. As interceptor drones, new radars and new guns enter service from different manufacturers, the same principle has to extend to the choice of response: which layer engages which threat, and who authorises it.

The Army has also pushed drones down to battalion level, with Ashni platoons in all 380 infantry battalions. That places sensors and potential effectors far forward and in large numbers. Without a common layer to coordinate them, each of those units has to strike the balance on its own.

Where Driif stands

The cost-exchange debate is often framed as a hardware race: who can build the cheapest interceptor fastest. Cheaper effectors matter, and India should have them. But in our view, the balance is ultimately won or lost in the seconds between detection and engagement, and that is a software problem.

Nexus, Driif’s counter-UAS orchestration layer, is built around that view. It is designed to bring tracks from radars and sensors made by different manufacturers into one operational picture, help classify what is approaching, and set out the available responses across units with their trade-offs visible. It recommends; the operator decides. Every engagement is authorised by a person, and every recommendation, decision and outcome is recorded so it can be reviewed afterwards.

Nexus does not replace any radar, gun or interceptor. It sits above them as part of Mission OS, so that the hardware India is already buying can be used in the right proportion. The aim is not to make engagement automatic. It is to make sure the person authorising it has what they need to choose well, and quickly.

When the balance is struck well, there is little to see. The drone falls, the expensive interceptor stays in its launcher and the stockpile is still there next week. When it is struck badly, the cost shows up later, as a magazine that runs dry before the threat that mattered arrives.

Drones will keep getting cheaper for the attacker. Defenders cannot match that through spending alone. They can match it through better decisions, made faster, with the right information in front of the people responsible for them. That is the invisible part of the balance, and it is where the next advantage will come from.

Sources