Year before last I had a problem with Bald Faced Hornets. They would swoop down and do snatch and grabs off the landing board. I saw one actually enter the hive. A short time later, a dead hornet was carried out by several honeybees and I saw a hand full of dead hornets on the ground. The honeybees would try to fly them away from the hive but weren’t able to get far.
I built a couple homemade traps and hung them in the trees away from the hive.
2 liter plastic soda bottle
Drill a 1 inch hole just below the slope on the neck
Add: 1 cup water, 1 cup sugar, 1 half cup vinegar, 1 banana peel
The best time to do this is in the spring when the hornet queens are out and about, starting new nests. Kill the new queens and eliminate the problem before it starts. This trap also works for the wax moth.
Another option that works very well for yellow jackets and hornets ……take a can of cat food or tuna fish and mix in a couple drops of flea/tick treatment. The hornets/yellow jackets will carry this home and the whole nest will die off. Just make double sure other animals can't get to it in any way. Honeybees don't eat meat and are not attracted to it.