Actor Existence Failure: Hiroshi Tsuburaya passed away in year 2000. So during the 2001 OV Once Again Gaia, Tabata (his character)'s absence was claimed to be making interviews in Bosnia.
Contest Winner Cameo: Episode 40 "I Want to See Gaia!", in which a boy named Taro is given the opportunity to visit XIG Aerial Base, was part of a contest where kids could have a chance to appear in an episode of Ultraman Gaia.
What Could Have Been: Fujimiya and Agul were originally meant to be Put on a Bus with episode 26 "The Final Resolution", but their surprising popularity from the fans allowed them to return in Episode 36 "The Sky of Reunion".