The Airliner has a transponder and a radio. Pretty sure the drone does not.
The transponder code, assigned by various ATC would identify that aircraft as a civilian airliner when it checks in, and on the screens of the SAM operators.
Also, the speed and altitude of the airliner, even approaching Grozny would not be the same as a drone. Airliners, even on approach, are somewhat faster, probably 200-250mph, or faster, and much higher in altitude, at least 5000ft, probably more like 10,000ft until close to the airport.
The transponder code, assigned by various ATC would identify that aircraft as a civilian airliner when it checks in, and on the screens of the SAM operators.
Also, the speed and altitude of the airliner, even approaching Grozny would not be the same as a drone. Airliners, even on approach, are somewhat faster, probably 200-250mph, or faster, and much higher in altitude, at least 5000ft, probably more like 10,000ft until close to the airport.