Why use a fly swatter when you can pick off flies with an "a salt gun".  The new Bug-A-Salt Rifle does just that.  I found tons of videos demonstrating this device and they all say it works VERY well.

YouTube

Man I'd like to have stock in these things. They run about $40 and they're going to tell ten million of them.  You can order yours from Amazon here.  Here's a guy named Tony giving you a demo of the product. I especially like how he pulls out the poster at the end.  Of course you're always one beer away from pinging your friends in the ass too.