Hmmm, NATO can fly over Libya about as soon as they decide that they want Israel to be involved in a fracas within a day or two of them doing so.
Recall that Saddam Hussein launched Scuds at Israel when ge got attacked by the coalition in 1991.
If Assad thinks he's going down, he's gonna do some damage on the way out.
That's how I see it. I am guessing the Israelis have asked the NATO and altruists mucking about to lay off of Assad.
Also, you will find that the Arab League did NOT ask the UN et al to intervene in Syria, unlike the Libya deal.
After that long ansewr: not any time soon, NATO planes over Syria.