Syrian
There's no No Fly Zone in place in Syria; no foreign military intervention to speak of. No foreign military aircraft in the airspace, even in an AWACS role. The Syrian government consider this to be an insurgency (albeit a heavily fought one), not a civil war.
They would argue there is no more reason for Syrian Airlines to cancel their flights than there was for BA to cancel flights to Belfast during the 70's and 80's, or for JAT to cancel flights during the Balkan wars of the '90's.
The insurgents have some AA capability, but not much. If they closed down the airline the government would be making a very significant admission of defeat.
I'm reminded of Air Rhodesia, which flew all the way through our civil war in the '70's, even after terrorists brought down two aircraft (Viscounts) near Kariba in 78/79. The government kept the airline flying despite the dangers, because they estimated that the propaganda value to the enemy of closing the airline was worse than the risk of casualties.