Originally Posted by
belynch
I'd look at DL or AA flights direct YYZ to JFK.
I was going to suggest the same thing, especially Delta because you'd get in earlier than AC and then you wouldn't have to reclear security at JFK (maybe at worst take a Delta shuttle bus from T2 to T4), assuming you could get an online boarding pass from SAA.
But then I realized the OP is checking bags, so you'd need to go outside security at Terminal 4 nonetheless.