report that John Brennan, the presidents deputy security adviser stated the U.S. government always "looks at what type of scenarios might unfold" and in accordance with that "looks at what types of contingency plans might be available."
Upon being questioned if the implementation of such a no-fly zone (probably over the northern Syrian city of Aleppo where government and rebel forces have been fighting for some two weeks) was being considered in the White House Mr. Brennan stated that "I don't recall the president ever saying that anything is off the table."
Brennan said the U.S. has "done a number of things in support of the opposition," and added that "there is a lot of humanitarian assistance that is going in there. What we want to do is to make sure that we understand exactly who are going to be the recipients of an type of aid."
Brennan also stressed that "the overwhelming majority of them [the Syrian rebels] are not of al-Qaeda ilk. They are Syrians who are truly trying to gain control of their lives and their future."
The crisis in Syria has been likened by -- among others -- former French president Nicolas Sarkozy to the Libyan uprising against the Gaddafi regime, which saw NATO intervene on the side of the opposition forces.
Republican critics of Obama's conduct with regard to the crisis in Syria have been calling for an international no-fly zone to be enforced to prevent the Syrian Air Force from operating over swaths of the country (most probably said rebel-held territories in the north). They have also called for directly arming the opposition (something America's allies in the region -- Saudi Arabia and Qatar -- are already doing) against Assad.
The U.S. for a large part however are wary of undertaking another military intervention in the Middle East following the costly wars of the past ten years in Afghanistan and Iraq.