The Krofft's sued McDonalds for copyright infringement because the characters of Mayor McCheese and Big Mac bore a strong resemblance to the Pufnstuf character. They also noted similarities between the living trees and the apple pie trees.
In spite of the show's seeming drug imagery (the psychedelic landscape, an episode prominently involving magic mushrooms, a character whose name is basically "Puffin' Stuff") creators Sid Krofft and Marty Krofft vehemently deny any drug connection.
Coral Kerr, well known character designer, is the creator of many characters for Sid Krofft and Marty Krofft's films and television series and for numerous other live action and animation productions since 1966. When she created the idea for what became "Freddie the flute", having been asked to come up with a sort of conscience for "Jimmy", which the character flute for the "H.R. Pufnstuf" series was to be, she found out 35 years later that Sid (and the two male members of what made up the art department) did not want to use the character for fear it would appear too phallic for a television show.
The H.R. Pufnstuf character was originally created for the HemisFair '68 world's fair in 1968, where the Kroffts produced a show called Kaleidescope for the Coca-Cola pavilion. The character's name was Luther and he became the symbol of the fair.
For Marty Krofft, the production of this show was a particular headache. Marty accepted guardianship of Jack Wild while the teenage boy was in America filming the show. He later described bringing Wild into his home as a mistake.
After Sid Kroft watched a rough cut of "Oliver" upon a request from his friend Lionel Bart, he immediately decided to ask Jack Wild for the lead role in this show.
Only two actresses auditioned to play Witchiepoo. The first was then unknown Penny Marshall, but it was felt that she wasn't right for the part. Stage veteran Billie Hayes came in next, set into a maniacal cackle and hopped up on a desk. She was given the part on the spot.
The idea of Living Island using buttons as currency was derived from Sid Krofft's childhood, as a kid he'd charged friends buttons, not pennies, to view puppet shows in his back yard.