Henry Winkler appears as his character, Arthur 'Fonz' Fonzarelli from "Happy Days". "Mork and Mindy" is a spin-off of "Happy Days", in which the character of Mork, as played by Robin Williams appeared in My Favorite Orkan (1978). This, along with Penny Marshall appearing as Laverne DeFazio, link together the two sitcoms.
Mork's Orkan Navy serial number includes "DDE". These are also the initials of President Dwight D. Eisenhower, whom Robin Williams played in one of his final films, The Butler (2013).