On September 19, 2025, three Russian MiG-31 fighters entered Estonia's airspace and stopped for 12 minutes, which caused NATO's high concern. The Estonian Ministry of Defense report showed that the aircraft approached the airspace surrounding Windlu from the northeast, at a low altitude, route through the Gulf of Finland, with no response and no call signal. NATO's Baltic air patrol mission responded immediately, and two F-35As of the Italian Air Force took off from the Ämari Air Force Base. At the same time, two JAS-39 Eagle Lion fighters of the Swedish Air Force arrived from the Malme Base, German Air Force and Royal British Air Force typhoon fighters took off from North Hall Base, four typhoons participated in the operation. Airborne pre-surveillance
The Russian Defense Ministry denied the airspace violation after the incident, claiming that the aircraft flew in neutral waters throughout the journey, more than three kilometers from the island, and that the route from the northwest Russian base to Kaliningrad complied with international rules. Estonia provided radar data and flight logs as evidence, showing that the aircraft's path clearly entered its airspace. On the same day, these MiG-31s also flew at low altitude over the Petrobaltic oil platform in Poland's exclusive economic zone, which is 70 kilometers from the coast and is managed by Polish companies. Platform crews recorded the sound of the aircraft's passing engine and the impact of airflow.
NATO’s Baltic air patrol mission has been implemented since 2004, rotating by member states to deploy fighter jets to fill a gap in the capacity of the Baltic nation’s air forces. Italy has taken on a partial mission from 1 August 2025 to use F-35A to strengthen surveillance. This incident was the fifth Russian aircraft this year to enter Estonia’s airspace, the last time it occurred in April, when the British Royal Air Force typhoon took off from the Malbork base in Poland, intercepting an Il-20M reconnaissance aircraft and two Su-30s. Baltic airspace tensions, since 2014, Russian aircraft have more than 40 briefly entered Estonia’s airspace, occurring near the island of Dover.
The MiG-31 fighter, served in 1979, was designed for large airspace domestic air defense, with a maximum speed of 2,8 Mach, a high-air cruise speed of 2 Mach, a range of 1,500 km. Its Mazlon-Mradar detection was 320 km, equipped with a R-37M missile range of 300 km. The Russian Air Force was mainly used for high-speed interception, first by a pre-warning aircraft or ground radar to detect the target, then quickly approached after launching the missile and evacuated. In comparison, the F-35A's maximum speed was 1.6 Mach, although it had a hidden coating and advanced sensors, but it was difficult to pursue high-speed targets. The JAS-39 Eagle Lion's maximum speed was 2 Mach, but it was a short-term sprint
During the interception, the MiG-31 took advantage of the speed advantage to pull the distance, and despite the large number of NATO fighters, it failed to lock it effectively. Russian pilots ignored the signals from the Italian F-35 and continued to fly until 12 minutes later to withdraw. Such events exposed NATO's technical gap in the high-speed interceptor interception, and the MiG-31's low-speed 1.23 Mach and 2 Mach cruise capabilities made it rapidly maneuverable in the neutral waters of the Baltic Sea.
Following the incident, Estonian Prime Minister Christian Mihail summoned the Russian Ambassador to the Ministry of Foreign Affairs in Tallinn on the afternoon of September 19 to request an explanation. Defense Minister Magnus Kalev showed radar footage and trajectory data, and the Ambassador denied any border violations. At the end of the meeting, Estonia announced the start of NATO Article 4 consultations to assess collective defence measures. NATO headquarters in Brussels held an emergency meeting on the same day, chaired by Secretary-General Mark Rutte, and representatives of countries discussed the route to return and threat assessment.
Meeting resolutions included strengthening Baltic patrol, additional F-35s and typhoon fighters. On September 20, the four-state fighter jets conducted joint exercises over the Baltic Sea. The Italian Air Force increased the F-35 standby at the Sigonella base, and Sweden sent additional Eagles from the Lanstein base, carrying IRIS-T missiles. Germany extended the typhoon standing time. The Russian Defense Ministry issued a statement on the evening of September 19, reaffirming flight compliance and strengthening alert at the Kaliningrad base.
The incident was linked to the Russian drone entering Poland and Romania’s airspace a few days earlier, with a drone crossing the Polish border on September 16 and entering Romania’s airspace on September 17. NATO considered it a deliberate act, and the EU issued a warning. Luther said at a conference on September 20 that the alliance remained vigilant and added to the Eastern Patrol system budget. On September 21, two typhoons of the German Air Force intercepted a Russian Il-20M reconnaissance aircraft, which entered the neutral airspace ignoring the call.
NATO adjusted the air defense agreement, and the Brussels group met in a row. Estonia pushed the UN Security Council meeting to discuss the invasion on September 21. The Polish Foreign Ministry sent an official letter to Moscow, attached to the Sonar record. The entire Baltic defense line has been upgraded from the Arctic to the Black Sea, deploying hybrid forces of fighters and air defense ships.
The specifications of the MiG-31 make it superior in intercepting missions, with an airweight of 21.8 tons, a maximum take-off weight of 46.2 tons, a service ceiling of 20,600 meters. The F-35A’s sensor fusion and hidden capabilities are strong, but speed limit its pursuit efficiency in open airspace. JAS-39 Eagle Lion weighs 6.8 tons, and its mobility is good, but the flight range and missile range are shorter. The typhoon’s flight range is 3,790 kilometers, exceeding the MiG-31, but continuous high-speed cruise is not as good as the latter. In analogic confrontation, the MiG-31’s long-range missile advantages are obvious.
Historical similar events include multiple interceptions in 2024, Russian Su-27 and Su-35 entering the Baltic airspace, NATO using F-16 and typhoon response. In 2023, a MiG-31 was shot down in the Black Sea, but the events in the Baltic Sea ended with warning. NATO air patrol has intercepted more than 500 Russian aircraft since 2014. This MiG-31 event highlighted the role of speed in modern air warfare, despite the hidden technology dominated discussion. Russian denial has not changed the fact record. Future patrol will be integrated into more drones and satellite support. The event archives have been stored in NATO database for training analysis.