Europe braces for potential direct clash with Russia as airspace incursions escalate

Europe’s security posture is shifting as a string of border violations and drone incursions by Russia tests NATO’s ability to deter and defend allied airspace. In the early months of the Ukraine conflict, Gen. Mark Milley, then chair of the Joint Chiefs of Staff, carried a note card outlining four priorities for the U.S. and NATO approach: avoid a kinetic war with Russia, contain fighting within Ukraine, keep alliance unity intact, and empower Ukraine to defend itself. The note reflected a precautionary blueprint designed to prevent escalation, a stance that has since been reframed as the risk calculus surrounding the war evolved. While Milley has left the role, observers say elements of that approach persisted as Western leaders wrestled with how far to go in backing Ukraine without widening the conflict. The past week has seen a visible shift toward accepting the possibility of a limited NATO–Russia confrontation, driven in part by a spate of brazen incursions into NATO airspace and increasingly explicit signals from European capitals about deterrence and defense.

On Sept. 8, a flurry of unmanned aircraft events underscored the new risk calculus. Twenty-one Russian drones crossed into Polish airspace, with some shot down by a coordinated operation involving Polish, German, Italian and Dutch forces. It is unclear whether all of the drones were en route to targets in Ukraine or whether some entered Polish airspace inadvertently on a path toward other destinations. Drones have repeatedly crossed borders into several NATO neighbor states since the war began, and their unmanned nature has long been considered a factor lowering the political threshold for more aggressive responses. A separate but related tension occurred when three Russian fighter jets violated Estonian airspace for about 12 minutes before NATO fighters intercepted them. Officials in Estonia said the incident involved manned aircraft and heightened concerns about the potential for miscalculation with a real human cost.

The drone events extended beyond Estonia as authorities in Copenhagen and Oslo shut down airports for several hours following drone sightings. A second Danish airport, used for both civilian and military flights, was closed briefly later in the week. Danish authorities subsequently linked the incidents to a state actor, though some governments and outlets continued to await formal confirmation. The episodes dominated discussions at the United Nations General Assembly in New York, where regional officials and ambassadors underscored the seriousness of border violations and the potential for escalation. Polish Foreign Minister Radosław Sikorski warned that if another missile or aircraft entered NATO airspace without permission and caused wreckage on allied territory, the alliance would respond decisively. While the UK’s foreign secretary similarly emphasized the need to defend NATO skies, former President Donald Trump surprised some observers by signaling support for shooting down Russian aircraft that violated allied airspace if asked to do so by European partners.

This week’s hawkish shift in tone comes as Western officials reassess how to balance deterrence with risk of broader confrontation. Analysts say there is little daylight between European capitals when it comes to defending NATO airspace, but questions remain about Washington’s level of commitment to a robust, long-term defensive posture. Some experts note that while European governments are moving to invest in air defense and drone-detection capabilities, political leadership in Washington may be more cautious about triggering a broader war with Russia than its European allies are comfortable with. A senior fellow at the Atlantic Council argued that repeated warnings without a strong, unified response send a mixed message to Moscow, and that there is growing momentum for a more capable “drone wall” and enhanced air-policing across eastern NATO members.

The drone and aircraft incursions have fed into a broader debate about how to respond. Lithuania’s parliament has authorized authorities to shoot down drones entering its airspace, illustrating a willingness to take rapid, decisive action if needed. Still, some analysts caution that any move to engage hardware risk turning a regional incident into a wider conflict. “If the Europeans are repeatedly warning Russia not to violate their airspace, and nothing happens, what message does that send?” asked a senior fellow and NATO analyst who emphasized that decisions in these situations may be made in minutes and require a delicate balance between escalation and de-escalation.

Other observers note Washington’s uneven levels of enthusiasm for a hard line. Liana Fix, a senior fellow for Europe at the Council on Foreign Relations, said there is uncertainty about whether the Biden administration, the vice presidency, and the Pentagon share the hawkish European instincts. She observed that some U.S. officials worry about becoming drawn into a conflict with Russia and have viewed the Baltic states with caution for this reason. The Financial Times reported that some Trump administration aides have complained about what they termed the “Estonization” of European defense policy, signaling a potential rift between Washington and its European partners on how aggressively to defend alliance borders.

The Baltic states have long urged greater vigilance, and the question of how to respond to Moscow’s tactics remains central as NATO assesses its options. Historical parallels, including the 2015 downing of a Turkish jet by Russia during an operation in Syria, continue to inform policymakers’ risk assessments. Although the 2015 incident did not trigger a wider clash, it underscored how quickly missteps can escalate into broader tensions among nuclear-armed powers. As the rhetoric grows louder, the overarching concern is whether the alliance can deter another violation before it happens or whether it must be prepared to respond when necessary—potentially with a punitive, proportionate action that could escalate rapidly.

Experts emphasize that the cost of allowing repeated airspace violations to go unanswered would be high, even as the risk of miscalculation remains. In the near term, NATO officials are prioritizing investments in air defense, border early-warning systems, and drone-detection capabilities in the eastern flank. A meeting was planned to discuss a coordinated funding strategy for a system of sensors, electronic warfare measures, and weapons designed to prevent further violations. But even with new investments, the consensus among many analysts is that deterrence is not a one-size-fits-all remedy, and each incident will demand careful, case-by-case decision-making that weighs the potential consequences of any action against the desire to avoid a broader war.

As the war in Ukraine grinds on, the world watches whether the current pattern of provocations can be contained within existing lines or whether the thresholds for collective defense will be permanently recalibrated. The risk of an irreversible slide toward a larger military clash remains a live concern for policymakers, diplomats and military planners across Europe and North America. While there is broad support for strengthening defenses and ensuring unity among NATO members, experts caution that the path forward will require constant vigilance, clear rules of engagement, and a willingness to adapt to evolving threats in air, space, and cyber domains.