I seem to recall (can't find the link now) that Ukraine declared their airspace closed to civilian aircraft after the Ukrainian Troop Transport plane was shot down recently.
Even if the airspace was open, it seems highly risky to fly over a battle-zone anyhow where direct radio communication with troops on the ground may not be possible, and opens a wide door for an accidental grounding, if not on purpose.
That being said, touching eastern Ukraine with a 30,000 ft. pole would probably be less than wise at the moment.
Yes, but without any direct communication, no organized Air Traffic Control, and without tracking satellites, it seems very easy for ground troops to mistake a civilian transport with a military transport.
Seems ludicrous for anyone to attempt to fly over Ukraine right now.
Except for the transponder...
This is now starting to appear very-much-so as an accidental grounding. The rebel's posted on a social network bragging about grounding another military troop transport, then quickly deleted the post as soon as the news broke about a civilian airline going down over Ukraine.