At up to about 3 inches in length, they truly are giant. They are commonly called “toe biters,” because as a type of true bug (piercing / sucking mouthparts) they can deliver a painful poke. They generally live in stagnant, slow-moving waters where they capture and consume other insects, small fish, frogs, and even snakes. Aside from finding them in the water, they are attracted to lights at night …which means, yes, they can fly.
Photo by: Glenn Marangelo on 5/1/21 in Clinton, MT