I'd call. I don't think you're worried about the flush here. You made a nice big bet on the flop, and even with AKs, I dont think he's hanging around with just a spade draw.

Could have been a mid-level PP that turned into a set, but I dont think you're seeing spades here. If so, what can you do? If he was that intent on seeing out a spade draw at less than 2-1 even though you were representing a made hand, well, what can you do?..except take his money in the long run.

I'd call.