How to deal with a flirty father-in-law?

So my fiance's father likes to flirt, as told to me by my mother-in-law in passing when telling a story. He hasn't been physically inappropriate and they've been married for over 40 years so I'm not taking it as anything more than joking around. It makes me kind of uncomfortable, though, but to me that's just more on personal differences than anything else. Ideas? I.e. they're right now on a trip together and first he sent me a message asking about snow and saying my fiancee was still asleep so I was all his and then a message than he's up so I'm no longer his (that "level" of flirting). Yes of course I can bring it up to my fiancee but I mean it doesn't bother me that much in the sense that all I'd do is ignore it and not respond but I don't want to be rude either. How to approach this? I don't want to make a mountain out of a molehill but I also would like the flirting to stop. Thanks for any suggestions :)

Ok GRKG Im gonna start out this way... Us men are like gorillas... The direct approach works wonders. So here's what you do. You confront him in a semi-private environment as a gesture of respect and simply explain the situation. One of two things will happen he will either feel shunned but will man up and knock it off or he will get on the defensive and start deflecting and maybe arguing by accusing you of something er other. The MOST IMPORTANT THING YOU DO WHEN DOING THIS IS... maintain you confidence. The stronger your confidence and will is the more likely he is going to feel the sincerity behind your words. And the awkward moment will move from you to him because you will know your justified to request that respect. Now if he gets defensive it will create waves but again STAND YOUR GROUND. Your not only marrying your fiance your marring his family ina sense. So you have to live with these folks and they with you. Lastly absolutely tell your fiance your uncomfortable prior to confronting your father in law. If the action persists then confront him. Afterwards as soon as possible let your fiance know. Hide nothing from him and do not make his father look bad when you explain it. You don't want to alienate yourself from clicking south the family. I think thats it if I remember anything else ill post again.

I knew I was forgetting something. Communication between youand your fiance is key to all this because it's going to be the glue to keep you two together. The good thing is if the family cohesion is strong enough then one way or another this is going to blow over. Assuming you make your self heard. If you don't do that things can swiftly spin out of control.