Air Defence, explained
July 27, 2025
Air defence systems protect places and people from aerial attacks, including from:
Drones: these could range from quick FPV drones smaller than 50 centimetres, to larger and slower loitering munitions such as the Shahed.
Missiles: these range from simple rockets handmade by militant groups or terrorists, to hypersonic cruise missiles which are more like pilotless fighter jets.
Aircraft: helicopters or planes can fire rockets, drop bombs, or use direct fire, including from long distances.
Short-range air defences can be handheld or mobile (also called self-propelled). These normally protect specific objects, locations or groups of soldiers.
Some systems fire regular rounds similar to a machine gun, while others use missiles or even lasers.
Medium- and long-range systems can protect a larger area, such as a city, from a variety of threats, including advanced aircraft.
How do they normally work?
An enemy missile, jet or drone enters detection range.
The radar system detects an incoming weapon and sends this information to the command centre.
The command centre calculates the weapon’s trajectory and where it can be intercepted, sending a signal to a launcher.
One of the launchers fires an interceptor missile that aims to explode close to the incoming weapon, destroying it.
Very long-range weapons focus on ballistic missiles that re-enter the atmosphere from outer space or fly at extreme altitudes.
These normally use a “hit-to-kill” method, aiming to strike the incoming weapon directly, instead of exploding nearby.
A layered structure is important for an effective air defence system as it allows for a more complete coverage.
No single system can counter all types of threats effectively.
Each layer compensates for the limitations of the others, ensuring protection if one layer is broken through.
Ukraine’s air defence
Since Russia’s invasion in February 2022, Ukraine has faced mass missile and drone attacks.
The use of drones by Russia has particularly increased since 2024.
Military and civil infrastructure in Ukraine is attacked daily with missiles, loitering munitions and drones.
Ukraine’s current air defence architecture has proven effective against Russian attacks, but this does not mean that all missiles and drones are intercepted.
Interception rates of Russian drones, particularly of the Iranian-designed Shahed, range between 80% and 90%.
On average, Russia attacks Ukraine with over 100 drones per day, meaning over 10 of them still hit the target.
Fibre optic drones are the latest innovation in drone warfare. They fly attached to a long cable which makes them immune to electronic jamming.
The interception rate of fibre optic drones is as low as 20% currently. However, they can only be used close to the front line and cannot target cities.
In 2022, Ukraine relied mostly on aging Soviet-era platforms (such as the S-300 and Buk systems).
As bombardments grew heavier, Western nations supplied advanced air defence systems.
In mid-2022, Germany supplied the first heavy air defence systems to Ukraine, the Gepard.
Western military aid has played a key role in strengthening Ukraine’s air defences.
Advanced systems supplied by the allies allowed Ukraine to build a multi-layered shield capable of resisting the mass attacks.
For example:
NASAMS batteries protect Kyiv against cruise missiles and drones.
Patriot batteries intercepted multiple hypersonic missiles, marking one of the first real‑world tests of such capabilities.
Patriot systems are important to Ukraine’s air defence due to their effectiveness.
However, each battery costs approximately $1 billion, with individual missiles priced between $4 and $7 million.
In July 2025, after an initial blockade, President Trump authorised the transfer of additional Patriot systems to Ukraine from US stockpiles. However, NATO allies will finance the restocking.
Ukraine has developed improvised and decentralised drone interception tactics.
Mobile teams equipped with Stingers and electronic warfare tools now patrol key sectors, responding to daily drone raids, especially around energy infrastructure and logistics hubs.
This innovation, mixing NATO modern systems and improvised countermeasures, has proven especially effective against Shahed drones, keeping their penetration rates below 20%.
For NATO and its allies, Ukraine is now a testing ground for modern integrated air and missile defences.
However, a major challenge is the cost asymmetry between offensive missiles and defensive interceptors.
For example:
Intercepting a single Russian Iskander ballistic missile often requires 2-3 Patriot interceptors, each costing around $4 million.
As a result, defending against a $3 million Iskander strike can cost up to $12 million.
This imbalance is a sustainability issue for Ukraine, especially as Russia continues to try and overcome Ukraine’s air defences by increasing the number of drones launched at the same time.
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Israel’s air defence
Israel operates one of the world’s most complex air defence architectures.
Israel’s air defence system is designed to counter threats ranging from rockets and drones to long-range ballistic missiles.
Each layer plays a complementary role.
The Iron Dome is Israel’s short–range air shield.
Iron Dome has been in use since 2011.
It is designed to intercept and destroy rockets, artillery shells and drones launched from 4 to 70 km away.
Iron Dome does not try to intercept every projectile. It automatically analyses each rocket’s trajectory and only intercepts those that would otherwise hit a populated area, not the desert.
This approach saves money and interceptor missiles.
Each interceptor missile costs approximately $50,000.
In recent conflicts, the Iron Dome has achieved interception rates above 90%.
David’s Sling is the medium-to-long-range air defence system, forming the second layer of Israel’s missile shield.
In service since 2017, it counters cruise missiles, large-calibre rockets and ballistic missiles at range of 70 to 300 km.
In May 2023, the David’s Sling carried out its first real-world interception, shooting down a rocket fired by Hamas.
In 2023, Finland and Germany signed contracts to buy David's Sling air defence systems.
David’s Sling interceptors each cost approximately $1 million.
The Arrow system forms Israel’s air shield against long-range missiles.
The Arrow program was launched in the 1990s to defend against long-range threats.
Today, the system includes two operational variants: Arrow 2 and Arrow 3.
These variants intercept ballistic missiles at different stages of flight.
Arrow 2 intercepts ballistic missiles while they are inside the Earth’s atmosphere. Each Arrow 2 missile costs around $2 million.
Arrow 3 defends against the newest, longer-range ballistic missiles, including those outside the Earth’s atmosphere. Each Arrow 3 missile costs around $3 million.
While Israel’s multi-layered air defence has shown its effectiveness, the recent escalation with Iran showed its vulnerabilities.
In 2024 and 2025, Iran launched 591 missiles and more than 1,000 drones at Israel.
Despite high interception rates, several missiles penetrated the defences, killing at least 28 civilians.
This shows how no air defence system can intercept 100% of the threats, and saturation is still a major challenge.
Saturation refers to the overwhelming of an air defence capability with numbers (by sending a lot of drones or missiles at once, complicating tracking and interception).
AI technology is increasingly used to boost the effectiveness of data analysis and calculations as part of operating air defences.
US air defence
Ground-based Midcourse Defense (GMD) protects all 50 states from intercontinental ballistic missiles, destroying them outside the Earth’s atmosphere.
GMD currently includes 40 interceptors located in Alaska and 4 in California.
GMD shoots down a missile in its “midcourse” phase, meaning before it begins the descent back into the atmosphere.
Terminal High Altitude Area Defense (THAAD) is a system designed to protect against missiles already in the final “re-entry” (“terminal”) stage of the strike.
THAAD is not currently covering the entire US, but it was deployed in Israel, Romania, South Korea and UAE, where it successfully shot down a missile fired by the Houthis.
In May 2025, US President Trump presented a project for a next-generation, multi-layered missile defence system, named Golden Dome.
The Golden Dome would provide advanced protection to the US homeland.
The system would use sensors and interceptors based on satellites in outer space to counter incoming advanced threats.
President Trump announced that the Golden Dome will cost around $175 billion but this figure could increase.
US air defence systems, especially Patriot, are an important geopolitical tool. Their supply is limited while the demand for them from countries experiencing conflict, such as Ukraine, is high.
Around 500 Patriot interceptor missiles are produced per year, with a waiting list of buyers.
The US is aiming to increase its production of these missiles and other military equipment.
In July 2025, Germany and the United Kingdom announced plans to jointly develop a European ultra-long-range interceptor system.
It will protect from hypersonic and ballistic threats, with a range of over 2,000 km.
Apart from Israel and the US, China and Russia also have the full range of air defence systems, from shoulder-fired equipment to radar guidance systems and “hit-to-kill” interceptors targeting ballistic missiles in the terminal stage.
It is unclear if any air defence systems can counter a large-scale strike with modern hypersonic missiles, but individual missiles can be intercepted, including by Patriot PAC-3 systems.
Author Simone Chiusa
Editor Anton Kutuzov
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