The closure of Aalborg Airport in northern Denmark this Sunday after drones entered its airspace is just the latest in a series of airport closures due to these unmanned aircraft.
Drones were also reportedly spotted above the airports in Esbjerg, Sonderborg and Skridstrup, in the west of the country, and a few days earlier they caused a temporary suspension of flights at the airport in Copenhagen, the capital of Denmark.
Danish Defense Minister Truls Lund Poulsen said that “everything points to this being the work of a professional actor,” adding that “it certainly doesn’t look like a coincidence. It looks systematic. I would define this as a hybrid attack.” Justice Minister Peter Humelgaard said he “is not ruling out anything about who is behind this.”
While there is no confirmation of Russian involvement in Denmark, recent incursions in eastern Europe have prompted NATO to call for action. Secretary-General Mark Rutte announced that the alliance was launching a new operation called “Eastern Sentinel” to protect its eastern flank in response to Russian drones entering Polish airspace. “Whether intentional or not, this is dangerous and unacceptable,” Rutte said.
Drones are such that they are difficult to identify, and dealing with them in an airport environment presents a completely different challenge compared to those that NATO or the EU are dealing with.
Why can't airports prevent drone incursions?
Drones, or various types of unmanned combat aircraft, have been used by militaries since the 1970s. Today, they are part of modern warfare, especially in Russia's war against Ukraine. The technology has also rapidly advanced in the commercial market, explains Richard Gill, founder and CEO of Drone Defence.
"Drones are becoming easier to obtain and use," he explains to DW. "And the price is falling. People can now do in their own workshops what only 10 or 15 years ago required advanced military capabilities."
This poses a serious problem for airports, which have to strictly control their airspace. "The Danish case has once again shown that drone flights over airports lead to the suspension of air traffic, because such a security risk cannot be tolerated," Jukka Savolaynen from the European Center for Countering Hybrid Threats (Hybrid CoE) tells DW.
This precedent, which has previously caused the closure of airports around the world — from New York and London to Dubai and Frankfurt — means that someone with bad intentions can cause serious disruption. But hobby drone pilots can also cause chaos and close down an airport when they make navigational errors. Drones are now cheap and readily available over the counter.
Why not just shoot down the drone?
In wars, drones are shot down all the time, but in peacetime, even when security services have doubts, it is often impossible to determine whether a drone is military or recreational. And even when it is possible, there are serious security concerns.
“It’s not easy to hit a drone with kinetic missiles, and you have to fire a lot of them to have a reasonable probability of hitting it,” says Savolaynen of the Hybrid CoE, which works with the EU and NATO on ways to counter hybrid threats. “Even if you do hit it, the vast majority of the missiles will fall to the ground. So I wouldn’t recommend firing them in densely populated areas unless the drone poses an immediate and serious threat.”
Given that the threat is difficult to assess, and airports are often located close to urban areas, the risk of collateral damage, coupled with the cost of shooting down a drone, makes it virtually impossible. Gil adds that, due to the rapid development of drones, legislation is lagging behind – and that leaves airports vulnerable.
“Not every airport has a detection system that is capable of determining what is happening. We usually rely on people on the ground, security or employees reporting that they see a drone. And then – how do you respond to that? If you decide to shoot them down, who is going to shoot?” asks Gil. Airports currently have no legal basis to shoot down drones.
Are there other ways to defend?
Airports, especially those that are not major international hubs, do not have many tools at their disposal. Identifying drones via radio frequency, video signals, radar or security cameras is one of the preventive measures. But stopping drones remains a major challenge even when they are spotted.
As a result, often suspending operations — usually a last resort — is actually the first option when drones are spotted in unauthorized space.
There are a growing number of drone-stopping products on the market, both in the commercial and military sectors. But improving airport defense systems is expensive and would likely require ongoing investment.
Ryanair CEO Michael O'Leary has suggested that governments should shoulder the cost of the problem, which he described as "irritating." "It's a safety issue for national governments. It's not something airports should be asked to deal with," he said.
The European Union, to some extent, agrees with this interpretation. European Commission President Ursula von der Leyen said on September 10 that the Union must “build a wall against drones” to counter the threat. “This is not an abstract ambition, but the foundation of a credible defense,” she said.
The “wall” is a joint project involving Poland, Finland, Estonia, Latvia and Lithuania, and aims to strengthen defenses on the EU’s eastern flank. It will use similar measures to airfields, but crucially, it may also be able to shoot down threatening drones – although details are still unclear. It will also reportedly be significantly cheaper to operate than existing air defense systems, which are designed for conventional aircraft and missiles.
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