Super Friends - Season 1 Episode 14
Gulliver's Gigantic Goof

Using his micro-wave reducer, mad Dr. Hiram Gulliver shrinks all adults- including the Superfriends- to two inches tall to help the population problem (by saving resources)... and also to rule over them (he will remain full-sized to watch over the mini population of the world). The Green Arrow joins the Superfriends to stop him and to return things to normal.