The first rocket planes ever to be mass-produced were the Messerschmitt Me 163 in 1944. Which other country used rocket planes during WW2?

The MXY-7 Navy Suicide Attacker Ohka (pictured) was a manned flying bomb that was usually carried underneath a Mitsubishi G4M2e "Betty" Model 24J bomber to within range of its target; on release, the pilot would first glide towards the target and when close enough he would fire the Ohka's three solid-fuel rockets. The Japanese produced approximately 850 Ohkas, and seven US ships were damaged or sunk by them throughout the war.