This a Queen Bald-face Hornet. The oueens over winter in ground litter and in the bark of trees. In the spring they build a paper nest and start a new colony.
Males are called drones. Born from unfertilized eggs. They don' have stings and are not aggressive.
The females can be Queens or workers. They have stings and will attack repeatedly. When away from the nest, they are looking for food and are non-aggressive, just don't swat at them.
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Hornets catch insects to feed to the larva in the nest. One hornet may catch 1000 flies a day. This makes them a beneficial insect. If you find a hornet's nest at your home, leave it alone or call a professional to remove it.