European aviation and Baltic tensions: Russia’s shadow over critical infrastructure

In recent weeks, European aviation has faced repeated disruptions from mysterious drone sightings, with authorities in multiple countries pointing fingers at Russia for orchestrating hybrid attacks aimed at sowing chaos and testing defences.

These incidents coincide with heightened alerts in the Baltic region over suspected sabotage of undersea cables, gas pipeline outages, airspace violations, and further drone incursions, leaving affected nations, the European Union and NATO scrambling for effective countermeasures.

The wave of drone disruptions began intensifying in late September 2025, starting with sightings near Copenhagen Airport in Denmark. On 22 September, two or three large drones were spotted, forcing the Nordic region’s busiest airport to halt all take-offs and landings for nearly four hours.

Similar incursions shut down Oslo Airport in Norway around the same time, diverting flights and stranding passengers. Danish Prime Minister Mette Frederiksen described the events as designed “to disrupt and create unrest,” linking them to a broader pattern of suspected Russian hybrid threats, including airspace violations in Poland and Romania, and hacker attacks on airports.

By 25 September, additional drone sorties closed airports in Aalborg and elsewhere in Denmark, prompting the government to classify them as hybrid attacks combining military and covert tactics.

These aviation woes extended to Germany, where drone sightings over Munich Airport on 2 October led to the cancellation of 17 flights and diversions affecting nearly 3,000 passengers on the eve of a national holiday. Bavarian Premier Markus Soeder called for police powers to shoot down drones, highlighting the vulnerability of critical infrastructure.

Both runways at Munich airport were closed on 3 October evening for the second time in less than 24 hours after drones were again sighted, leading to dozens of flights being diverted or cancelled and stranding some 6,500 passengers, authorities said.

Earlier, in Poland, nearly 20 Russian drones violated airspace on 10 September, prompting NATO jets to shoot down several – the first such instance since Russia’s invasion of Ukraine. This forced temporary closures at Warsaw Chopin, Modlin, Rzeszow, and Lublin airports, reigniting fears for civil aviation safety across Europe.

Experts note these events expose gaps in counter-drone technology, with the International Air Transport Association (IATA) warning that such systems remain costly and underdeveloped for widespread airport use.

Suspicions that drones disrupting Danish airspace were launched from Russia’s shadow fleet have intensified, underscored by a French raid on a suspected vessel, though it yielded no concrete evidence linking the ship to the incursions.

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On the night of October 2-3, 2025, approximately 15 unidentified drones were detected flying over the Elsenborn military base in eastern Belgium, near the German border, marking the first such incident reported in the country amid a broader wave of mysterious drone activity across Europe.

Compounding these aerial threats, the Baltic region has been gripped by a series of undersea infrastructure incidents since Russia’s 2022 invasion of Ukraine. Undersea fiber-optic cables linking Finland and Germany, as well as Sweden and Lithuania, were severed in November 2024, with suspicions of deliberate sabotage by dragging anchors from vessels possibly tied to Russia’s shadow fleet.

In December 2024, the Estlink 2 power cable between Finland and Estonia was damaged, alongside four telecom lines, leading Finnish authorities to seize a Russian oil tanker suspected of causing the outage.

Airspace violations persist, including Russian MiG-31 jets entering Estonian airspace for 12 minutes on 19 September, intercepted by Italian F-35s.

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Drone sightings and GPS jamming have also endangered vessels, as noted by Polish Admiral Krzysztof Jaworski, who described Russia’s tactics as a “hybrid war” testing NATO’s resolve.

Russia consistently denies involvement, with the Kremlin dismissing allegations as “absurd” and accusing NATO of warmongering.

Western intelligence, however, views these as escalating hybrid threats, including sabotage, disinformation, and cyberattacks, aimed at Ukraine’s allies.

The EU and NATO’s responses have been multifaceted but challenged by coordination and resource gaps. NATO launched the “Baltic Sentry” mission in January 2025, deploying frigates, patrol aircraft, and naval drones to safeguard undersea infrastructure, with expansions including air-defence frigates following Danish incidents.

The alliance’s Maritime Centre for Security of Critical Undersea Infrastructure in London maps vulnerabilities and conducts exercises like “Freezing Winds” to enhance resilience.

In response to drone threats, EU leaders endorsed a “drone wall” – a network of sensors and weapons along Europe’s eastern flank – during a Copenhagen summit on 1 October, prioritizing defences against unmanned aircraft.

Allies like France, Germany, and Sweden dispatched anti-drone systems and troops to secure Denmark’s EU summits.

The European Commission pledged nearly a billion euros for cable surveillance and emergency repair fleets, while pushing sanctions on Russia’s shadow fleet.

NATO Secretary General Mark Rutte emphasized a “determined response” to proven sabotage, and Baltic states like Latvia urged bolstered air defences.

Yet, challenges remain: constant surveillance of vast seabeds is impossible, and reactions like Denmark’s civilian drone ban highlight reactive measures over prevention.

Analysts warn that without capacities to respond and unified protocols, these incidents could escalate, potentially invoking NATO’s Article 5 if state involvement is confirmed.

Analysts note that if NATO invokes Article 5 in response to such provocations but fails to deliver a decisive response – due to internal divisions, U.S. reluctance under potential policy shifts, or fear of broader war – the alliance’s deterrence credibility would erode, signalling to adversaries that collective defence is unreliable.

This erosion would represent a strategic victory for Putin, as undermining NATO’s cohesion could embolden further aggression, reduce support for Ukraine, and allow Russia to expand influence in Europe without facing unified opposition – effectively fracturing the transatlantic security architecture that has deterred Moscow since the Cold War.

To counter this, experts urge clearer red lines on hybrid threats, enhanced countermeasures like drone defences, and unified sanctions to restore deterrence before provocations escalate.

Caption: A ‘No Drone Zone’ sign at Brussels aiport while a Brussels Airlines passenger plane takes off, Brussels, Belgium, 26 September 2025. EPA/OLIVIER MATTHYS