Syria's already poor air force is wearing out:
The Syrian Air Force has suffered major losses in the last year, as the aircraft and helicopters were unleashed on rebels (and civilian supporters) and took a beating. Of the 370 usable fixed wing war planes the Syrian Air Force had two years, about half are now out of action because of combat losses or wear and tear. Nearly two-thirds of the 360 helicopters are gone, for the same reasons. ...
Syrian Air Force losses have been heavy, with some 400 aircrew dead, captured or missing. Nearly a hundred fixed wing and over a hundred helicopters have been lost. About half of these aircraft were captured or destroyed on the ground as rebels attacked, and often captured, air bases. The jets (and a few transports) were hit while landing and taking off and this threat often led to airbases being abandoned, with aircraft incapable (because of damage or lack of spare parts) of flying out being destroyed or just left behind.
Strategypage also notes use of heavy automatic weapons for anti-aircraft use--12.7mm and 23mm guns.
Like I've said, stop focusing on Syria's air force. Russia won't let us set up a UN-backed no-fly zone? Who cares?
I say beat Assad on the ground by maximizing the killing of his infantry:
[The] best way to help the rebels deal with Syrian air power is to help the rebels put the airfields under threat. Small numbers of truck-mounted (or towed) 120mm mortars would help with that in addition to the lighter rockets and mortars.
I just don't think Syrian air power is as decisive as is being made out to be. Rebels were doing better even when Syrian air power was more active. Rebel reverses have taken place not because air power has become better, but because Assad has more troops for the space he is trying to control.
Assad has abandoned the fight for large parts of Syria and has added tens of thousands of loyal militias and thousands of Hezbollah troops to make up for the loss of infantry in the fight over the last two years. The rebels need weapons to kill that new infantry. The militias are not well trained and the Hezbollah too few to take many casualties and remain effective. Kill them and the air power has nobody to support.
This war will be won on the ground where Assad's minority base of support can least afford casualties.
