NATO’s test in Estonia’s sky breach

On 19 September 2025, three Russian MiG-31 fighter jets entered Estonian airspace near Vaindloo Island in the Gulf of Finland, according to Estonian authorities. The aircraft reportedly remained for about twelve minutes, flew without a flight plan, had their transponders switched off, and failed to respond to calls from Estonian air traffic control. NATO responded by scrambling Italian F-35s under its Baltic Air Policing mission, while Estonia summoned Russia’s chargé d’affaires in Tallinn and requested consultations under Article 4 of the North Atlantic Treaty.

At first glance, some might see the incident as just another fleeting episode in a long series of Moscow’s provocations. No shots were reported fired, no lives were lost. But dismissing the violation as a mere nuisance would be a mistake. In reality, it was a deliberate test of NATO’s resolve, a reminder of how fragile Europe’s security architecture remains, and a sign that Russia’s appetite for risk and intimidation continues undiminished.

At the heart of this incident lies the principle of sovereignty. Airspace is as inviolable as land. To send military aircraft across a neighbour’s border without clearance, without transponders, and without communication is not an accident; it is a statement. For Estonia—a nation of just 1.3 million people sharing more than 180 miles of border with Russia—the breach is deeply personal. For small states, sovereignty is both priceless and precarious. Every violation, however brief, undermines the credibility of the international system that promises security through law. If Estonian skies can be trespassed without consequence, what message does that send to other NATO members with vulnerable borders?

The alliance reacted swiftly: fighter jets scrambled, diplomats summoned, Article 4 invoked. Article 4 is not a routine gesture. It signals that Estonia perceives a direct threat to its security and seeks collective reassurance. While Article 5—the mutual defence clause—has never been triggered by an airspace violation, repeated incursions test the credibility of NATO’s deterrence. If Moscow perceives hesitation, it may calculate that the alliance is unwilling to escalate over “minor” breaches. But what starts as a dozen minutes of unauthorised flight can, in moments of miscalculation, spiral into a full-blown crisis.

Airspace violations carry more than symbolic weight. They pose real risks of mid-air collisions, misidentification, or overreaction. Jets flying “dark” without transponders complicate civilian air traffic safety in crowded skies over the Gulf of Finland. A passenger plane travelling between Helsinki and Tallinn could, in theory, cross paths with a military jet engaged in a dangerous game of brinkmanship—with catastrophic results. Intercepts themselves are fraught with danger. NATO pilots closing in on intruding aircraft must rely on signals and split-second judgements. A wrong manoeuvre, a misunderstood gesture, and the world could wake to headlines about a downed aircraft and a crisis spiralling out of control. Estonian officials have noted that rules of engagement are in place for such situations—underscoring how close the region already is to the possibility of escalation.

This year alone, Estonia reports four separate violations of its airspace by Russian aircraft. Across the Baltics, provocations have become almost routine: planes skirting borders, ships navigating aggressively close to territorial waters, and cyberattacks probing critical infrastructure. These actions are not random. Each breach chips away at the sense of normality and safety in the region. Each tests NATO’s reaction times, political will, and thresholds for response. To normalise violations is to concede ground in the contest of perception—and in deterrence, perception is everything.

For Estonia, Latvia, and Lithuania, such provocations are existential. For the rest of Europe, they are a reminder that geography and alliance commitments tie their fates together. An attack on Estonia, however improbable some may think, would be an attack on all of NATO. Too often, western European capitals have treated Baltic concerns as alarmist—shaped by painful history and close proximity. Yet time has repeatedly vindicated the Baltics’ warnings: about Russia’s actions in Georgia, in Ukraine, and now in the skies. Ignoring or downplaying the seriousness of airspace incursions risks repeating the mistake of underestimating Moscow’s willingness to test boundaries.

Words of concern are not enough. Concrete measures are necessary to restore deterrence and reassure Estonia and its neighbours. NATO must consider reinforcing its Baltic Air Policing mission. Rotational deployments may no longer suffice. A more permanent allied presence—aircraft, air defence systems, or surveillance assets—would send a stronger signal of commitment. The alliance should also explore targeted consequences. If Moscow pays no price beyond a diplomatic summons, it has little incentive to stop. Economic or political costs tied specifically to airspace violations could alter the calculus. Europe must invest in resilience, upgrading radar coverage, integrating air defence networks, and ensuring seamless NATO-EU coordination. 

A breach near Vaindloo should trigger an automatic, unified response. At the same time, diplomacy must remain on the table. Clear communication of red lines, firm but measured responses, and channels for de-escalation are vital. The goal is not confrontation but prevention—through visible readiness. Russia’s airspace intrusions are not just about Estonia. They are part of a global contest over norms. If borders can be violated without consequence, then the international order frays further. The lesson of Ukraine is not confined to Donetsk or Kherson; it reverberates in the skies over Tallinn, the seas near Riga, and the corridors of NATO headquarters in Brussels. The message to Moscow must be unmistakable: the alliance will not be divided, and sovereignty is not negotiable.

Some will argue that responding strongly risks overreaction. Better to shrug it off, the logic goes, than to stumble into confrontation. But history teaches the opposite. Aggressors are emboldened by passivity, not firmness. Estonia’s skies may seem distant to those in Paris, Berlin, or Washington. But treaties bind allies precisely so that no member stands alone. A breach near Vaindloo is a breach in the security of the entire alliance. To treat it lightly is to invite the next, and more dangerous, provocation. NATO was built not only to defend territory but to defend the principle that borders matter. If that principle erodes, the costs will be paid not just in Estonia but across the continent. Now is the moment to make clear: the skies of Tallinn are as inviolable as the skies of Berlin, Paris, or New York. Twelve minutes of trespass must not be allowed to unravel seventy-five years of peace.