How many movies have Glenn Leopold and William Hanna collaborated on?

They have worked on 6 movies together! Their first movie together was Lucky Luke: Daltons on the Loose (1983) while their highest rated movie together was Scooby-Doo on Zombie Island (1998). They have not worked together since Scooby-Doo and the Alien Invaders (2000). They are most known for their animation films together.