Wasps are not popular insects with most people, as they don't provide many of the same benefits as honey bees and yet are extremely aggressive. Many animals don't care for wasps and avoid them, so there are several insects whose main protection from predators is that their appearance makes them look like wasps.
Hover flies, also commonly referred to as flower flies in many places, are insects that look like small wasps. They are yellow and black in appearance with stripes, and are often found around flowers and in gardens, which even puts many of these flies in the same environment as the wasps that they are mimicking. There are literally hundreds of different subspecies of hover flies, and there are also larger hover flies that mimic bumblebees or other larger species as opposed to wasps.
There are winged ants who who look like black wasps. There are no flying ants that fit the stereotypical version of a wasp, but many winged ants do look surprisingly similar to black wasps. These ants are part of an organised ant colony, and can be identified from the actual black wasps based on size and flying movement. Black wasps will be larger and have a thicker thorax than flying ants. Wasps also have a different flight pattern from the mimicking winged ants.
Central American Katydids
One of the flying insects that most looks like a wasp is found in Central America. Wasp-mimicking katydids in Central America are orange and black and look very similar to the local tarantula hawk wasps. What is interesting about these insects is that they even fly like wasps, flying in a jerky wasp-like fashion. However, when night arrives, they move like normal katydids, with slow and deliberate movements.