Although the rebels have been able to shoot down several aircraft after capturing some heavier weapons from military bases, they are largely helpless when it comes to Assad's air supremacy.
The opposition has repeatedly asked their foreign backers for weapons that can shoot down the regime's aircraft and help hasten the fall of Assad. But the United States and its European allies have been reluctant to provide opposition fighters with anti-aircraft missiles for fear they may end in the hands of radical Muslim groups that have been the most organized fighting force on the opposition side.
The rebels also want a no-fly zone established over northern Syria, but the countries opposed to Assad have taken no action on that option, either.
The top U.S. military commander in Europe, Adm. James Stavridis, said last month that some NATO nations are looking at a variety of military operations to end the deadlock and assist the opposition forces, including using aircraft to impose a no-fly zone, providing military assistance to the rebels and imposing arms embargoes.
As with U.S. and international involvement in Libya in 2011, a resolution from the U.N. Security Council and agreement among the alliance's 28 members would be needed before NATO takes a military role in Syria, Stavridis said.
Late last year, NATO deployed Patriot batteries along Turkey's border with Syria, with the alliance's leaders emphasizing that the missiles will not be used to shoot down aircraft operating in Syrian airspace.
Military experts say it is unlikely the West will revisit the no-fly zone any time soon.
"It's not easy to just go on and establish a no-fly zone, and the West has said so before," said Beirut-based military analyst, Brig. Gen. Hisham Jaber, a retired Lebanese army officer who heads the Middle East Center for Studies and Political Research in Beirut.