Star Trek IV: The Voyage Home/Fridge

Fridge Logic

 * Chekov left his phaser, communicator, and identification onboard the USS Enterprise... that is, the "nuclear wessel".
 * Chekov's phaser didn't work, the identification was laughed off as a fake, and the communicator useless to anyone without 23rd Century or later communicators to talk to. They were most likely tossed aside as useless props owned by a Commie agent. Conversely, given the Stable Time Loop that seems to happen with Scotty giving away transparent aluminum, the tech from Chekov's "props" could be used to found the technology Cochrane would need to build his warp drive.
 * They were seized by The Men in Black and taken to Area 51.
 * Clarified in the novelization, where Chekov grabbed his things before leaving the ship, and threw them into the water before he was captured again.
 * The movie's premise makes time travel in the Star Trek universe seem much too easy. We can only assume that that ship was special because it belonged to Christopher Lloyd.
 * Maybe, but it wasn't without precedent in the series -- this was actually the third or fourth time they'd used that method of time travel. Plus it did have its limits, in that it caused huge stress to the ship that was attempting it, and the range was apparently limited to a few centuries in either direction.
 * Fourth, actually. They did it three times in TOS. Twice on purpose.
 * The movie does indicate that relatively small miscalculations could have bad effects in timewarp. They risk it here because, well, it is the only plan they manage to come up with.
 * Time travel in Star Trek IS easy, it's just generally a bad idea.
 * So what happened to Maltz from Star Trek III the Search For Spock? Surely if the Federation sent a ship to pick up a Klingon prisoner, they would have picked up Kirk and company as well. Did Maltz spend the entirety of Star Trek IV in the bird-of-prey's brig?
 * Given the Klingon mentality it doesn't seem likely that Klingon birds-of-prey would be equipped with dedicated holding cells--Maltz might have spent time in some sort of high-security closet.
 * Maybe they left him on Vulcan.
 * The film mentions that Sarek's diplomatic powers are what's keeping the Federation from just arresting Kirk and company. Odds are he wouldn't have been inclined to offer Maltz the same protection.
 * In the Novelization, we learn Maltz committed suicide.
 * However, the Expanded Universe has Maltz still alive in the 24th century.
 * It wasn't even necessary to give the 20th century transparent aluminum. The guy at the factory said that they could build the whale tank with six inch thick plexiglass. So why didn't they just do that?
 * That's exactly what they did do. They traded the Transparent Aluminum formula for the materials they needed. They only had $100 in cash to begin with after all, so they bartered with information.

Fridge Horror

 * While it's great and all that the Planet is saved at the end, eventually, they're going to have to repeat this mission. At best, a humpback can live about a hundred years; if George and Gracie's kid lives that long, the humpback will go back to extinction around Picard's time.
 * Keep in mind that people in the 24th century seem to have mastered cloning.
 * The novelization explains that there are samples of humpback whale DNA preserved on Earth, but that without a pre-existing whale to teach the clones how to act like humpback whales, there would be no point. Presumably these samples are used to boost the population to a self-sustaining level.
 * Spock tells McCoy that he cannot discuss what it was like being dead unless the other person in the conversation has a similar frame of reference, i.e. has been dead themselves. Everyone seems to be forgetting that 2 members of the crew have been dead before: McCoy died on the Shore Leave planet, and Scotty was killed by the Nomad probe!
 * Except that the manner of Spock's death; the transfer and re-insertion of his Katra into a rejuvenated body is a kind of death-resurrection experience that only a Vulcan can possibly have.
 * Since it's now been established that it's perfectly fine to take a 20th Century person back to the 23rd... might there be some other reason Spock insisted so strongly "Edith Keeler must die"?