The FAA has banned ALL U S carriers from overflying the region since April, 2014. Just today, Air France, Virgin, Lufthansa, others have FINALLY followed that advice and are re-routing all of their flights as well. Too bad that the European and other carriers had to await a tragedy to put safety before economics, having some more expense now avoiding direct line overflights.
And I would be very careful of speculation as to the cause of the tragedy. A full investigation lead by INTERNATIONAL authorities, not Ukrainian, not Russian, not Donetsk will sort out EXACTLY what happened