By Stefanos Skamagas,

Terrorism remains an unpredictable and evolving threat, with its methods constantly adapting to new technologies, tactics and security measures. Historically, terrorists have embraced readily available tools and innovations to maximize or facilitate their impact and damage. Just as conventional warfare evolves, so does the asymmetrical warfare waged by non-state – and proxy – actors. The use of unmanned vehicles, and especially UAVs/drones, represents a significant – and expected – new frontier in this evolution.

To understand the potential of drones, we must look at how terrorist groups have historically adopted new methods. Often, these methods prioritize accessibility, lethality, and a high psychological impact relative to their cost. A great example of a low-cost, high-impact attack is the 2004 Madrid train bombings, which were estimated to have cost only around $10,000 [1], while the 2005 London bombings reportedly cost even less, with the total death toll to have reached 191 victims [2] in the first case and 52 victims for the second one [3]. The key to these attacks was the use of improvised explosive devices (IEDs), which can be constructed for as little as a few hundred dollars using common materials from your local market and the comfort of your home. This demonstrates a clear pattern of prioritizing methods that are cheap to produce but cause the possible maximum destruction and fear.

In the terrain of terrorism, specific actors made the headlines multiple times, groups like ISIS, for example, gained notoriety for specific, brutal tactics like suicide bombings and public beheadings. This wasn’t just about causing death, it was about creating a unique and horrifying brand that instilled fear and attracted media attention. Similarly, the use of car bombs in Escobar’s Colombia served as both a weapon and a symbol of his power and reach. Despite these “common” methods, ISIS used UAVs platforms in order to cause damage, but also for propaganda and ISR (intelligence, surveillance, reconnaissance) reasons, specifically during 2014 to 2017, in POIs, like Mosul, with the use of consumer drones (DJI-type quadcopters and small fixed-wing models) to carry small explosives, grenades, or incendiary devices [4]. Another example of the use of these platforms for domestic damage is the attempted drone assassination of Venezuelan President, Nicolás Maduro, in August of 2018, during a military parade, with the use of two small multirotor drones carrying explosives. [5]

The New Frontier
The proliferation of commercially available drones makes them an attractive and logical next step for terrorists. Their capabilities offer a new set of tactical advantages that align perfectly with the historical goals of terrorist organizations. Unlike a suicide bomber or a car bomb, a drone attack allows the perpetrator to be in a safe distance from the target, greatly reducing the risk of capture or elimination (if it’s not intended). This shifts the risk-reward calculation for a terrorist group, enabling them to conduct multiple attacks without sacrificing personnel. Despite that, UAVs can be used for sophisticated pre-operational surveillance, allowing for precise targeting of individuals or infrastructure. In an extended scenario, the use of AI and pre-programmed flight paths could allow for autonomous “one-way” attacks. A drone could be launched from an abandoned building and programmed to strike a target at a later time, long after the perpetrator has left the area of possible danger for itself. This further enhances the ability to avoid detection and capture. And finally, as we have already witnessed from the Russia – Ukraine war, a group could launch multiple, cheap drones simultaneously to overwhelm a target’s defenses. This “swarm” tactic presents a complex challenge for conventional air defense systems designed to counter larger, faster threats (ex Ukrainian Operation “Spider’s Web”).

Cost and Accessibility
While a commercial drone can cost several hundreds or thousand dollars, this is still a relatively low capital investment compared to other, more traditional forms of terrorism (e.g., funding a large-scale, coordinated attack like 9/11). Moreover, the cost is decreasing, and the knowledge to build a drone from a 3D printer for around $350 makes the technology even more accessible to lone-wolf actors or small cells. This echoes the shift seen with IEDs, which can be built with inexpensive materials, allowing terrorists to create chaos for a minimal financial outlay. [6]

On the Ukraine–Russia frontlines, the most common short-range kamikaze drones are FPV quadcopters and modified commercial models like DJI Mavics (approximate cost of 500$ to 3.000$ per unit). FPVs type drones carry 1–2 kg warheads, have ranges of about 3–12 km, and are fast and maneuverable for precision strikes, while Mavics are valued more for reconnaissance but can be adapted for light attacks. Their main weaknesses are short battery life, small payload capacity, and high vulnerability to electronic warfare—jamming, GPS spoofing, and signal interception—which can disable or misdirect them. Both sides continually adapt with hardened control links, improved methods like fiber optic UAVs, alternative frequencies, and even low-tech defenses like netting to counter these threats. [7]

Psychological and Symbolic Dimensions
The psychological impact of a drone attack could be profound and long-lasting, creating a new kind of pervasive fear. A drone attack could be framed as a symbolic act of retaliation against a nation that uses drones in military conflicts (“eye for an eye”). The perpetrator could claim to be using the enemy’s own technology against them, creating a powerful propaganda narrative. At the same time, the fear of the unseen, the sound of a drone overhead could become a new source of anxiety, PTSD, similar to the psychological toll reported by individuals in conflict zones, which based on video footage, a serious number of individuals/soldiers move forward with a suicide act when they detect the UAV and they are unable or hopeless to avoid the immediate sudden result. The constant fear of an attack from an unseen enemy could cause widespread psychological trauma and social disruption, a primary goal of terrorism.

Countermeasures & Security Challenges
While the threat posed by UAVs is increasingly recognized, countering them presents a unique set of operational and technological difficulties. Traditional air defense systems are designed to detect and neutralize larger, faster-moving aircraft or missiles, not small, low-flying drones that can be even smaller from a backpack. As such, an effective response requires a combination of detection, deterrence, and interdiction measures tailored to this new threat.

One approach is the deployment of specialized detection technologies such as radio frequency (RF) scanners, acoustic sensors (like passive sonars in submarines), and short-range radar systems capable of identifying UAVs based on their electronic signatures or unique sound profiles. These systems can be integrated into “drone shield” networks that provide early warning in high-risk areas. However, such equipment is often expensive, has limited coverage, and may struggle in dense urban environments where buildings interfere with line-of-sight sensors and there are multiple sources of noise and frequency.

Once a drone is detected, neutralization presents further challenges. Counter-UAV tools range from signal jammers that disrupt the communication link between drone and operator, to high-powered microwave weapons or kinetic interceptors like net-launching projectiles. While effective in controlled environments, these methods are not without risk—jamming may interfere with civilian communications, while shooting down a drone over a crowded area risks injury and collateral damage from falling debris.

Finally, there is the challenge of scalability. Protecting a single high-profile event may be feasible with concentrated counter-drone assets, but providing continuous protection for all vulnerable public spaces—stadiums, transport hubs, government buildings, monuments—is logistically and financially impractical. This reality underscores the need for layered defenses that combine technology, intelligence gathering, operator training, and public awareness campaigns.

Risk Assessment & Probability Analysis
As it has been analysed earlier, this emergence diffusion have changed the baseline risk environment for terrorist actors. Over the last decade transfers and local production of drones—both hobbyist and militarized—have expanded worldwide, lowering the material and technical barriers for non-state use. This proliferation is well documented in recent datasets and analyses that track international transfers and indigenous manufacturing, showing a steady increase in capacity among state and non-state actors alike.

Because drones are dual-use (as nearly every subject), cheap, and adaptable, credible threat assessments from major security agencies now treat the use of UAVs by violent non-state actors as not only plausible but increasingly likely in certain theatres and contexts. U.S. and allied homeland threat reports, and specialist studies on unmanned systems, explicitly highlight UAVs as an evolving means for surveillance, precision strikes, and even as components in multi-vector attacks, with these assessments emphasizing that the technology’s accessibility makes opportunistic or copycat attacks more probable over time. [8]

When evaluating likelihood versus impact, it helps to separate tactical, operational, and strategic scales. Tactically, small kamikaze drones and FPV systems have already been used successfully in conflict zones to strike personnel, light vehicles and multi million dollar platforms. These attacks are relatively cheap and technically feasible for motivated groups, so the probability of local, small-scale UAV incidents is high in permissive or contested areas. Operationally, coordinated swarms of dozens or hundreds of low-cost drones can overwhelm point defenses and cause localized but significant damage to infrastructure or concentrated gatherings. Given recent examples in modern conflicts, the probability that an organized group could mount a crippling operation against a poorly defended facility or event is moderate. Strategically, for an attack that produces mass casualties comparable to major terrorist events of the past, the probability is lower but non-negligible, as the complexity required (logistics, payload, targeting, and avoiding countermeasures) is substantially greater, and state-level or supply-chain facilitation is often a prerequisite. [9]

Estimating the likely scale of damage requires assessing probable payloads and attack profiles. Commercial and FPV drones typically carry small explosive loads (0.5–5 kg range), sufficient to kill or injure people in close proximity, destroy soft vehicles, or start secondary fires in vulnerable infrastructure. Damage to hardened targets (fortified military facilities, reinforced critical infrastructure) is less likely from single small drones, but coordinated salvos, use of larger loitering munitions, or attacks that combine kinetic drones with cyber or physical vulnerabilities can produce outsized effects (for example, temporary disruption of energy or transport hubs). Historical incidents and vulnerability studies therefore suggest governments should prepare for casualties in the tens to low hundreds in the most severe non-state cases, and for intermittent but disruptive outages to key services if attacks are well planned or state-enabled. [10]

Electronic warfare and counter-UAV measures materially change the calculus of probability and impact. Jamming, spoofing, and hardening of command-and-control links reduce the effective range and reliability of many commercial-grade systems, while layered detection (radar, RF detection, electro-optical sensors) and kinetic or directed-energy interceptors increase the cost and complexity for attackers. That said, attackers adapt: switching to autonomous flight profiles, pre-programmed GPS paths, mesh control networks, or lower-observable trajectories reduces vulnerability to jamming and makes attribution and interdiction harder. Recent threat reports note that as countermeasures improve, so do adversary tactics, creating a continuous offense–defense cycle that must be priced into risk models. [10]

Finally, preparedness should assume continued evolution:, as AI, autonomy, and improved propulsion extend range and loiter time, and as commercially available platforms grow in payload capacity, the envelope of plausible attacks expands. This implies that probability estimates must be revisited frequently and that resilience measures, such as redundancy in critical systems, rapid incident attribution and response, public-private information sharing, and adaptive legal frameworks, are as important as point defenses. In short, policymakers should treat the drone threat as a rising, adaptable risk, expect more frequent low-to-medium severity attacks, keep the possibility of a rarer high-impact event on the books, and invest in layered, flexible mitigations that reduce both likelihood and consequence.

Sources
1. Schippa, C. (2017, November 15). How terrorists fund their attacks – and how to stop them. World Economic Forum. https://www.weforum.org/stories/2017/11/terror-attacks-are-increasingly-self-funded-how-can-we-stop-them
2. Stigler, A. B. G. (2009, March 11). The 3/11 Madrid bombings: An assessment after 5 years. The Wilson Center. https://www.wilsoncenter.org/article/the-311-madrid-bombings-assessment-after-5-years
3. Greenberg, N., Wessely, S., & McFarlane, A. (2012). Psychological consequences of the London bombings. In A. D. La Greca (Ed.), Mental health and disasters. Cambridge University Press. https://www.cambridge.org/core/books/abs/mental-health-and-disasters/psychological-consequences-of-the-london-bombings/12B92CAE749E66AC5FBBFB262239C881
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6. Malyasov, D. (2024, January 15). What Ukraine’s drones really cost. Defence Blog. https://defence-blog.com/what-ukraines-drones-really-cost/
7. Hennessey, M. P. K. (2023, August). On the horizon: The Ukraine war and the evolving threat of drone terrorism. Combating Terrorism Center at West Point. https://ctc.westpoint.edu/on-the-horizon-the-ukraine-war-and-the-evolving-threat-of-drone-terrorism/
8. U.S. Department of Homeland Security. (2024, September 30). 2025 Homeland threat assessment. https://www.dhs.gov/sites/default/files/2024-10/24_0930_ia_24-320-ia-publication-2025-hta-final-30sep24-508.pdf
9. United Nations Office of Counter-Terrorism (UNOCT) & Counter-Terrorism Committee Executive Directorate (CTED). (n.d.). Module 5: Unmanned aircraft systems. United Nations. https://www.un.org/counterterrorism/sites/www.un.org.counterterrorism/files/2118451e-vt-mod5-unmanned_aircraft_systems_final-web.pdf
10. Mehra, T. (2023, November 1). The exploitation of generative AI by terrorist groups. International Centre for Counter-Terrorism. https://icct.nl/publication/exploitation-generative-ai-terrorist-groups