A super easy wasp trap is to cut the top quarter off the top of a plastic soda bottle. Leave a couple of spoonfuls of soda (not diet) in the bottom or a bit of sugar water. Take the part of the soda bottle you cut off, remove the lid, and place it upside down in the bottom portion of the bottle. The wasp will enter the bottle drawn to the sweet liquid, and not be able to find their way back out. They will drown. This is an awesome thing to have on hand around campsites and picnic areas.
Keep in mind, when you smash or crush a wasp, they release pheromones that draw other wasps. This method is a bad idea.