Baldfaced hornets are beneficial because they reduce the numbers of flies and other insects (including even other yellowjackets) by using the live insects as protein to feed developing baldfaced hornet larvae inside their paper nest. Adult hornets are also beneficial native pollinators.
During the warmer months, avoiding the area around a nest that is near the ground or buildings is the best course of action because the hornets will aggressively defend them. A hard freeze should kill any insects still in the football-shaped paper nests that become visible once the leaves are gone from the trees. Overwintering queens survive by finding a protected place under bark or in buildings. The queen will emerge in spring to lay eggs and begin a new nest with workers that enlarge the home of the new colony.
Thanks for your question!
-Naturalist Dottie Drockton