Originally Posted by
drewguy
Stuff happens more in China though. Randomly cancelled and delayed flights because of military operations.
IME, military operations along trunk routes are much less common these days than they were in previous years. That having been said, "stuff" definitely happens more in China than other places.
I am 95% confident that the OP will be fine with a 4 hour layover, but I would be 95% confident with a 2 hour layover in any airport in the USA.