With virtually every airline now avoiding to fly above east Ukraine like the airborne version of the plague (observed recently in Denver) for obvious reasons, here is a snapshot of what the sky over east Ukraine looks like courtesy of FlightRadar 24.
It is, in brief, a ghost sky.
The highlighted plane belong to Ukraine Airlines. All the other, yellow, ones are doing their best to fly well inside Russian borders.
And zoomed out:
The real-time interactive map can be found here.