Are you suggesting the Il-20 had no crew on board?
Ohh, sorry. No they are not drones. They do have a crew. They are basically a passenger plane with the responder turned off. I don't know if they did radar clocking, but since Copenhagen ATC couldn't see them at all they might have.
I don't know why I called it a drone just because they kept radio silence. I guess the right term would be a ufo :-)
And I was a little frustrated that they send a plane that is a lot cheaper to use than the F16 we usually use to intercept them. And sending a plane from Denmark to intercept them, only makes sense if we choose to do so when they are far away from Copenhagen approach. If not, then we suddenly have 2 planes from 2 sides in Copenhagen approach that doesn't belong there.
But I guess that is the game. We only choose our move. ( But 'we' I mean our military and civil air administration )