Only a no-fly zone can curb chemical attacks in Syria

"The UK parliament voted not to take military action after Ghouta and not to support Barack Obama’s plan for strategic strikes to take down Assad’s command and control capability and destroy key sites and chemical weapons facilities. The British vote unfortunately made Obama recalibrate. It is interesting to hear Ed Miliband, who wants to be the UK’s next prime minister, claim responsibility for this inaction as a demonstration of his gravitas and statesmanship. I, for one, believe it is the greatest strategic military mistake this century. It kept Assad in power – with the result that thousands more are dead and injured – and fuelled the rise of Islamic State. Had the attacks gone ahead as the US wanted, the ensuing situation would certainly not be worse than it is today, and at the other end of the scale the Assad regime could have fallen and IS stopped in its tracks."
I don't believe the US did want to take action, like Cameron, Obama wanted to be seen to be trying to do something without actually getting involved, and risking that Islamists would replace Assad in Syria. I think there is another way to stop the chemical attacks, give the Free Syrian Army the anti-aircraft weapons they have been asking for since 2012. If there were a No Fly Zone over Idlib only, it might well save some lives, even getting there seems hedged with so many qualifications that like the train-and-equip programme for a US proxy army to take on ISIS, it may take so long to get off the ground that it may be over-taken by events. I haven't actually seen any evidence that Syrian and Iranian jets have been attacking ISIS in Syria; they have attacked civilians in ISIS-controlled areas, so I don't see that a country-wide no fly zone stopping such attacks would be a bad thing. On previous evidence, even if a no fly zone were established in Idlib, previous experience would suggest the régime would up its barrel bomb attacks in all other areas. I'm mindful that one of the stupid arguments against arming the FSA was that the Russians would just up their weapons supplies to Assad; I'm not saying an Idlib no fly zone would make things worse, just that it may not be the answer.
Two comments so far, one pretends that Syria is Iraq, the other repeats Seymour Hersh's genocide denialist claim that the rebels used chemical weapons on themselves to provoke US intervention.