[emeraldice]

I really doubt you're up against a set or a flush here; aforementioned villain is most likely shoving a flush draw on flop/ raising sets, like you said. It's possible he has KJ. I might go for a smaller value bet though, seems like 1/2 to 2/3 pot gets called by an underpair or a jack more often than shove? A shove seems like a pretty obvious AK.