Creator Backlash: Bruce Kalish has gone on record to say that in hindsight, the treatment of Sam was not his finest moment.
Development Gag: "Abandoned" ends with a friendly alien saying "Maybe I'll go to New Zealand. No one will ever find me there!"
Piggy gets teleported there in another episode.
Doing It for the Art: Greg Aronowitz designed a lot of the alien makeup for background characters on his own time and dime.
Enforced Method Acting: "History", the Dino Thunder cast was not allowed to see the Doggie Cruger suit until they actually started shooting scenes with him so that they really would be surprised by his appearance.
Executive Meddling: Disney wanted to save money and didn't want to hire a seventh starring actor, so it was written in that, Sam the Omega Ranger, As a side effect of time traveling, he was either stuck in his suit or transformed into a ball of light. This meant he was played on set by a stuntman in a bulky helmet and had his dialogue recorded later in ADR, making interaction between him and the other characters incredibly awkward. Apparently, the crew was so frustrated by this that they tended to write around Sam as often as possible; they probably would have written him out entirely if not for stock footage constraints. Additionally, Jason David Frank was not happy when he was not invited back for the team-up episodes as a cost-cutting measure.
Prop Recycling: A number of alien extras have been seen using parts of previous monster costumes. One of the most noticeable was in "Dogged", where a guy on Gruumm's ship had Deviot's head.
The flashback with Cruger wielding a Spiral Saber and wearing a similar cloak to Andros's.
The monster on Sgt. Silverback's planet aka Silverback, testing the Rangers by using a hologram is actually Beetleborgs monster El Scorpio.
Hey look, a bunch of furry suits we've never seen come to help us along those we do know! Yeah, they'll be immediately recognized by Dekaranger viewers. Two of them were replaced by redesigns, the other two didn't make the cut.
The A-Squad's duty uniforms are the jumpsuits worn by the Dekarangers, which presents an odd contrast with the much fancier uniforms worn by the rest of SPD.
Piggy's cafe is a treasure trove of this. Monsters from Time Force, Lightspeed Rescue and other seasons, along with a Tenga and a gatekeeper from the MMPR movie (which, incidentally, executive producer Greg Aronowitz worked on). Even an unused GoGoFive (Lightspeed Rescue's sentai counterpart) monster made an appearance.
It Makes Sense in Context: Well the premise for this series was that Earth had become a haven for many extraterrestrials by this time, so many of the aliens in existence from Morphin' on being around is actually plausible.
The usage of In Space helmets for the A-Squad and Time Force suits back when Sky's father was a cadet.
Recursive Import: The show was dubbed in Japanese (And the 1st Disney-era PR to be dubbed in that language, Mystic Force would come later) — the last case of this was Power Rangers Lightspeed Rescue. The Dekaranger cast dubbed their Western counterparts, save for Kat Manx, who was voiced by Rie Tanaka.
What Could Have Been: Originally the producers wanted to make Jack's counterpart a girl (Which would have given us the first female Red to have the title for an entire season), but Disney vetoed the idea.
A film that would take place after the series and would involve Jack rejoining the team was considered, but Disney rejected the idea. Ironically Toei would start an series of Super Sentai films for the 10th Anniversary of an series with Dekaranger being the second with basically the same plot concept.
You Look Familiar: Kelson Henderson, who appeared as a one-shot character in Dino Thunder, gets a regular role as not-quite-Ascended Fanboy Boom. You'll be seeing him in every series for a while.
The only Disney-made season of the franchise where all of the main actors were all American or Canadian.