Trivia: Shortly after the battle begins, Bard rides to Dale to look for his children. A woman tells him she saw them in the old marketplace. When he starts to go there, a man comes running and shouts 'the Orcs have taken Stone Street'. That is an in-joke: Stone Street is the name of Peter Jackson's film studio.
Trivia: Fans may be unaware that Billy Boyd, who played Pippin in the Lord of the Rings movies, sings the end-credit song, "The Last Goodbye."
Trivia: This film has both the final acting role for Ian Holm, who played the older Bilbo, and the final live-action role for Christopher Lee, who played Saruman. (His only roles after were voice-overs.) Holm passed away in 2020, while Lee passed away in 2015.
Answer: When Aragorn was 25 he left Rivendell to travel the world, having had his proposal to marry Arwen rejected by Elrond. Hence he is absent during the time period of the Hobbit, having gone to Rohan and then Gondor in disguise. During his travels he becomes very well known among the Elves, owing to Elrond raising him and Galadriel welcoming him to Lothlorien after he comes back from his long travels. Even before, he had served in the Rangers of the North as he was growing up, where he gained the nickname Strider. Legolas already knows Aragorn before LoTR, as Aragorn had initially left Gollum in the care of the wood-Elves before someone helped Gollum escape.