Dubai: Air defence systems in Gulf states intercepted large numbers of Iranian missiles and drones during the opening months of the US-Israel-Iran war.
Yet deadly Houthi attacks on Riyadh’s international airport have exposed a troubling question: How did missiles and drones travel more than 1,000km and penetrate Saudi Arabia’s defences?
Saudi Arabia is investigating why its air defence systems failed to stop the barrage that struck King Khalid International Airport, killing at least 13 people and wounding more than 300, according to two regional officials cited by the Associated Press.
Initial findings suggest the Iran-backed Houthis launched multiple drones ahead of a combination of cruise and ballistic missiles, potentially complicating Saudi efforts to detect, track and intercept the incoming weapons.
The investigation is also examining why the kingdom’s air defence network failed to provide earlier warning.
The attack raises wider questions about the effectiveness of sophisticated missile defence systems against attacks involving multiple types of weapons.
The sophistication of the attacks also raises questions about how the Houthis, once a largely guerrilla force, acquired the technology, technical expertise and operational capabilities to challenge advanced air defence systems.
Iran has long been accused of supplying the Houthis with missile components, weapons technology and technical training, helping the group develop increasingly sophisticated missile and drone capabilities.
Why manoeuvrable missiles are harder to intercept
How do ballistic missiles work? Ballistic missiles are powered by rockets during their initial flight before following a largely predictable trajectory towards their target. They can travel at extremely high speeds, giving air defence systems limited time to respond.
What are manoeuvrable warheads? Unlike conventional ballistic warheads, manoeuvrable re-entry vehicles (MaRVs) can alter their flight path as they descend towards a target. This makes it harder for defence radars and interceptors to predict exactly where they will travel.
How are cruise missiles different? Cruise missiles use engines to fly through the atmosphere, often at low altitudes. Unlike ballistic missiles, they can follow changing routes and use terrain to reduce their visibility to radar.
Why are drones difficult to stop? Drones generally fly more slowly than missiles but can be small and difficult to detect. Large numbers arriving together can complicate air defence operations.
Can Patriot systems intercept them? Patriot systems are designed to counter several types of aerial threats, including ballistic missiles. However, interception depends on factors such as the incoming weapon’s speed, trajectory, radar detection and available response time.
The key point: Manoeuvring warheads, low-flying cruise missiles and coordinated drone attacks present different challenges. No single air defence system can guarantee that every incoming threat will be intercepted.
Why the attacks were difficult to stop
The effectiveness of modern air defence systems depends on several factors, including the type of missile, its trajectory, speed, altitude and the time available to respond.
Ballistic missiles generally follow high-altitude trajectories that can be detected by long-range radar. Cruise missiles, however, can fly at lower altitudes, making them harder to identify against terrain and other background interference.
Drones present another challenge. They can be smaller, slower and more difficult to distinguish from other objects, particularly when deployed in large numbers.
A combined attack involving drones, cruise and ballistic missiles can force defenders to track multiple threats simultaneously, potentially stretching radar coverage, command systems and interceptor resources.
Saudi Arabia operates US-supplied Patriot missile defence systems, but even advanced interceptors cannot guarantee protection against every incoming weapon.
The Iranian missile comparison
During the opening weeks of the Iran war, regional defence systems reported intercepting large numbers of incoming ballistic missiles.
But the Riyadh attack illustrates an important limitation: A high interception rate against one pattern of attack does not necessarily guarantee the same result against a different combination of weapons.
The Houthis possess missiles equipped with manoeuvrable warheads capable of changing direction during flight, according to AP. Such capabilities can complicate interception by Patriot batteries and other defence systems.
The precise sequence of the Riyadh attack, and whether the Houthis deliberately overwhelmed Saudi defences, remain under investigation.
What happens next?
The security implications extend beyond Riyadh airport.
Saudi officials want Washington to become more directly involved in countering the Houthis. The United States has provided intelligence, targeting assistance and operational planning, but has so far avoided direct strikes in the latest Saudi-Houthi confrontation, AP reported.
President Donald Trump said on Saturday that Washington was considering military action following the airport attack.
Such intervention could widen the conflict and threaten shipping through the Bab Al Mandeb Strait, a crucial gateway to the Red Sea.
The Saudi-led coalition has also been fighting to regain territory seized by the Houthis near the strategic waterway.
For Saudi Arabia, the immediate challenge is determining how its defences were breached and whether changes in radar coverage, early-warning arrangements or interception tactics are needed.
The Riyadh attacks underscore a fundamental challenge of modern warfare: Even sophisticated air defence networks cannot guarantee protection against coordinated missile and drone strikes.