3. The Voyage Home (1986)
The only Star Trek movie that seems like a Christmas movie is The Voyage Home. Whales, fish-out-of-water comedies, and time travel all have the same clear message: we need to care about the weakest species in the present to protect the future. The group needs to depend on each other and the compassion of strangers because they don't have their usual supplies.
What makes it especially heartwarming is how light it is on cynicism. The movie radiates camaraderie, including Spock's journey to find himself and the crew's promise to face the repercussions together. It looks like the universe is saying that doing the right thing, even if it puts you at risk, is still worth celebrating when Kirk and his officers are reinstated. Spock and Sarek's heartwarming exchange and the USS Enterprise-A's reveal at the end only sweeten this emotional must-see Trek.