Kihunters fly in the air and will swoop down and attack with their claws when Samus gets close. You will often have to jump and shoot or fire diagonally to take them out. In addition, if a Kihunter takes enough damage, its wings will fall off. A clipped Kihunter hops around and can still attack with its claws, but it will also spit a caustic acid. Kihunters are best dispatched with the Charge Beam or any other high-powered beam weapon or with Missiles.
Kihunters can take a good deal of firepower to take down, especially the ones in the Wrecked Ship. If you do not have a powerful beam weapon, use Super Missiles instead.
Lower Norfair Kihunters should only be killed with the Screw Attack. Don't bother using anything else.