I can't imagine flatting here, but IF flatting is good then you should be squeezing with your air here 100% of the time.

As played I'd call it off if both players know you're capable of squeezing and are capable of thin stack-offs. UTG can be moving in quite wide here and the flatter can have JJ or AK that didn't see value in 3-betting an UTG raise, but now thinks he can stack off given all the dead money in the pot. If either of them is a nit in big pots then folding might be more prudent, and regardless this would be the bottom of my range for stacking off.