Well if the missile came from the "rebel" side (read: Putin's merry band of rascals...), then Ukraine needs to be a NATO member next week..
If it came from the Ukrainian side, which I doubt, then the bunch in power in. Kiev need to go, pronto! And that's going to get complicated..
Whatever the outcome, it will not be a good one, but taking civil air trafic hostage to regional conflicts cannot be tolerated, and I will support whoever gets this point across! Too bad all the big players have already lost the moral high ground on this particular subject...