Use a bounty system for Syrian pilots who defect with their aircraft and give them income. That is cost effective. It worked in Angola in the 1980's. The Cuban pilots were offerd a bounty to fly their MI -24 gunships to a particuler neutral country. They were to be given many times over what the communist were paying. The Cuban generals were so paranoid they grounded the entire airforce briefly. This aviodable carnage must end for the Syrian people who have been enslaved to the Assad family for generations. De Oppresso Liber.
Two mortar shells explode in Golan Heights, no casualties or damage reported (Haaretz)
from the article: Syrian pilot defects, uses jet to bomb army positions