An aircraft carrying Ukraine's president is reported to have come into proximity with a drone while flying to Oslo. Authorities are establishing what occurred.

The precise location and altitude, and the type of drone, were not immediately released. Several European countries have reported rising numbers of drone detections near airports and on air routes.

A new variable in civil aviation safety

Drones are small enough to evade radar and take time to trace back to an operator. Sightings near airports have repeatedly caused temporary suspensions of take-offs and landings.

European aviation safety bodies and national regulators are expanding detection equipment and tightening registration. Flights that cross borders, however, require coordinated procedures.

The wartime context

In airspace adjoining Ukraine, keeping military drones separate from civil traffic remains a standing problem, and airlines continue to route around certain corridors.

Once the inquiry reports, it should be possible to say whether the encounter was incidental or deliberate.