The yellow jacket wasp is about 3/4" in length and can resemble a bee from a distance though bees have more hair and are duller in color. Also, yellow jackets like to frequent areas with food (human or pet) or compost piles rather than flowers. Be especially careful if drinking soda outside as they are attracted to the sugary fluid.
If a nest is found, it is best to avoid the area as the wasps are more aggressive near their nest. These are beneficial insects as they feed on soft bodies insects such as caterpillars and sawfly larvae and should not be destroyed unless the nest presents a danger to people. Rather concentrate on removing food sources near areas you frequent as much as possible. This includes picking up and disposing of fruit that may have dropped from fruit trees. (Ward Upham)