Turkish Airlines is facing questions after one of its passenger flights from Tallinn to Istanbul reportedly entered Russian airspace, taking a non-standard route for the service, Estonia’s Eesti Ekspress and public broadcaster ERR.ee reported on July 22.

According to Eesti Ekspress, the aircraft on July 12 flew over Russia's Kaliningrad exclave instead of following its standard route through Latvia, Lithuania, Poland, Hungary, Romania and Bulgaria.

A passenger told the newspaper he noticed the deviation using a flight-tracking application and asked cabin crew about the change. After consulting the cockpit, the crew reportedly said the route had been chosen deliberately because the pilots considered it the most efficient option.

Estonia's air navigation service provider, Lennuliiklusteeninduse AS, said the approved flight plan did not include Russian airspace and was intended to pass through six European countries before reaching Turkey.

Taivo Linnamagi, head of aviation at Estonia's Ministry of Climate, said flights over Russian territory are regarded as unsafe for civil aviation because of the ongoing war in Ukraine and the associated security risks.

Although Turkish Airlines is permitted to use Russian airspace, flight-tracking data indicate that routing flights between Tallinn and Istanbul via Kaliningrad is uncommon.

The airline had not commented on the reported incident at the time of publication, Eesti Ekspress reported.