Military exercises and spontaneous drills will likely increase due to the political situation in the East and South China seas so further delays are actually very probable.

There are major airbases in the Nanjing military region covering Shanghai so the airports worst affected by these military drills are usually PVG, SHA, HGH and NKG.

Old recipe is to favor early morning flights to and from these airports. Personally I've switched to HSR almost completely and will also use trains to and from Hong Kong once the new Kowloon terminal opens.