whether this is true or not, it is the reason that the americans won't/can't provide the rebels with air support.
in a doomsday scenario, the americans would no doubt win. but, they'd have to eat a dozen f-*s and swallow a huge amount of pride in the process.
the rebels were supposed to take out the sam sites from the ground, first, to allow for massive strikes - but they couldn't do it.
as an aside: the day that israel can no longer assert air superiority over the broader levant is the day that the balance of power in the region shifts. this was always the fear, here: that syria is going to emerge from this much more powerful and much more assertive than they were at the start.
they should have let assad step down peacefully when he wanted to, years ago. and, the architects of this failed war in syria should be sent to the hague.
https://sputniknews.com/middleeast/201703171051691543-israeli-plane-downed-over-syria-analysis/