I understand that some kind of buffer is needed for the humanitarian aid to be distributed to refugees but two problems strike me.
The first is unilateral action on the part of the U.S. I personally don't have a problem ignoring the UN, it's a bunch of thugs and dictators for the most part, but Obama and the rest of the worlds liberal internationalists constantly scream to all the world the need for the "international community" to act as one in these kinds of endeavors. Has Obama realized that that point of view is childish an unsustainable? I doubt it. Some kind of election year warmongering? Wouldn't be the first time but seems unlikely for Obama.
While trying to understand the mind set of a socialist megalomaniac is a pointless venture, trying to understand how an aerial blockade would even work here isn't. To the best of my knowledge the entire conflict is contained inside Syria. I don't believe the Syrian air force, if it exists, is participating in the slaughter. Knowing that, how does an aerial blockade work? Are our planes going to fly around and target Syrian military forces that seem to be engaging civilians? Are we just protecting aid workers? How does this stop the Syrian government from killing people?
When we had the fighters securing Iraq after the first Gulf War, it made sense. Iraq had some planes and were moving heavy military around that we could target and destroy. If we are going to destroy Syrian military in a city environment while they are engaged with civilians, that seems like a recipe for disaster. We may very well destroy large percentages of active Syrian military but can't help but kill high numbers of civilians as well. On the other hand, if that's not what we are trying to do with the aerial blockade, then what are we doing? Nothing else will save any lives.
This smells faintly like Vietnam-era decision making where Washington theorists are trying to determine the most mathematical way to get this done. If we are willing to bomb cities in an attempt to keep the Syrian government from killing them why not just invade with the goal of regime change? We did it in Afghanistan, Iraq and virtually in Libya so why not here as well. Seems like a hell of a lot better than an indefinite bombing campaign with hazy objectives and limited possibilities for success.