Yesterday Nico Voorbach (ECA) said on Dutch TV that if Russia closes its airspace to European airlines, Russia would risk being kicked out of ICAO. That would be the end of Russian connection to the outside world.
I can provide you with the link where mr. Voorbach said this, but it is in Dutch...
http://www.eo.nl/tv/knevelenvandenbr...nk-e6bfe9e6ee/