They’re still using MiG-21’s? They would be about as effective as Nieuport 17’s against today’s Israeli Air Force.
The bulk of the Syrian Air Force is Mig-21’s and Mig-23’s.
In June 1982 the Israeli Air Force destroyed 86 Syrian aircraft during the battle of Bekaa Valley with no losses of their own. Most of them were Mig-21’s and Mig-23’s.
http://en.wikipedia.org/wiki/Operation_Mole_Cricket_19