2/4 Hand, A/K flop top pair and flush draw

[tradingman123]

I just wanted get everyone's opinion on this one. AZK, let me know if this deserves attention in the small stakes section.

Party 2/4 10 handed.

Hero (~300)is dealt A/K off on the button. Villain is BB with ~500. Sat down for 2 orbits, villain has played few hands and I have no read.

All fold to hero, I make it 16. SB folds and BB calls.

Flop is K/T/x all diamonds. I have Ad/Ks. BB cks, Hero bets 18 into 38 pot, Villain ck raises to 50... Hero?