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.
Alycia Purrott was memorably in the MTV TV-movie Jailbait a few years before SPD.
Mis-blamed: Bruce Kalish was not the one responsible for the increase in giant explosions. That would be Koichi Sakamoto. Despite this, even people who know this fact still refer to them as "Kalishsplosions."
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 Go Go V (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 suits for A-Squad and Time Force suits back when Sky's father was a cadet.
The only Disney-made season of the franchise where all of the main actors were all American or Canadian.
The Jetix website inexplicably lists Bridge's age as 17 - he outright states that he was a week old during the 2004 Dino Thunder team up, which puts him at 21 during the series. Given this mistake, it's difficult to say how old any of the other rangers are.