High pressure poison spray. There is an organic kind that IME works about as well as the synthetic ones: https://www.groworganic.com/products/ecosmart-wasp-hornet-ki...

Obligatory, https://en.wikipedia.org/wiki/Flamethrower?wprov=sfla1

More seriously, Hornets vs Spray Glue https://www.youtube.com/watch?v=GCLCewL5NVg

(note: he's still wearing a full bee suit—so hornets are probably best left to pros—unless you're properly equipped & very brave!)