Awesome, Dear Boy: James Cameron admitted that one of the main reasons he wanted to make this film was so he could personally dive down to the actual remains of the Titanic.
Beam Me Up, Scotty!: Rose asks Jack to "draw [her] like one of [his] French girls", not "paint her". For some reason, the latter is starting to show up frequently these days. Also, a common misconception is that she says it while naked; she actually says the line while fully clothed.
Blooper: In the opening sepia tone footage, we see a blonde girl in a straw hat waving out, but when the ship departs, we see her again and the shot is reversed. In addition, it appears that the latter shot has the correct orientation. In the sepia tone footage, it appears that she is waving out to sea.
California Doubling: Baja California, in this case - while there were scenes in the North Atlantic and even the actual Titanic wreck, the main filming location were in Fox's studios in Mexico.
Cast the Expert: All the crew aboard the research ship and its submarine are, well, actual research-ship-and-submarine crewmembers. Cameron hired the Akademic Mstislav Keldysh to visit the wreck, and kept them on payroll for use as set and extras once the production phase started.
Channel Hop: The film started out as a 20th Century Fox production entirely. As the production budget soared, however, Fox decided to sell the domestic rights to Paramount to hold off potential losses (they still released the movie internationally).
Creator Backlash: James Cameron has expressed some regret over how First Officer William Murdoch was portrayed (i.e. shooting a passenger and then himself), admitting that he'd been "thinking like a screenwriter" when he made the relevant decisions. After Murdoch's relatives and residents of his hometown complained, Cameron donated money to set up a charitable prize in Murdoch's name.
The Danza: Lewis Abernathy, who is not an actor but a friend of James Cameron, plays Lewis Bodine.
Deleted Scenes: An hour's worth of deleted material can be found on the Blu-ray. Some of these scenes were previously available on the mid-2000's DVDs. Several are based on events that actually took place over the course of the voyage and sinking.
Returning to her room after dinner, Rose freaks out and starts smashing everything before running to the stern.
Rose entering Steerage the day after her suicide attempt to find Jack. This included a break in the flashback in which Old Rose goes to rest while Brock laments to Lizzie that he's staked everything on finding the diamond.
On Sunday morning, Thomas Andrews shows Cal, Ruth, and Rose the gymnasium as part of their tour of the ship. Cal fiddles with the rowing workout, while Ruth says she "can't think of a more useless skill." On their way out, Rose punches a large punching bag. After that, Tommy and Fabrizio help Jack sneak into First Class. A crewman spots Tommy and Fabrizzio and scolds them as they walk away, but he misses Jack who has just made it to the first class deck.
The wireless operators Jack Phillips and Harold Bride are backlogged in their work, only to hear the Californian messaging them warning about the ice field the Titanic is about to steam into. They tell him to shut up. The Californian radio operator then shuts down for the night.
The death of Assistant Engineer Jonathan Shepherd, the historical "first victim" of the Titanic sinking, when he broke his leg and asked to be left behind in a flooding room so others could survive.
After receiving the order to send out the distress call CQD, Harold Bride suggests to Jack Phillips that they use the new distress call SOS. "It might be [their] only chance to use it." (In some countries, this scene made it into the theatrical version.)
Ismay goes into a panic upon grasping the seriousness of the situation, before being told off by Fifth Officer Lowe.
John Jacob Astor showing his wife what's inside a life jacket by cutting it with a knife in the gym, and the gym manager saying that he doesn't need a jacket because it will limit his stroke. Astor reminds him that they are 700 miles from the shore. (It can be found at the tail end of the above clip).
The Carpathia sequence was originally longer. Prior to the rescue, we have a shot of Lightoller and the men on Collapsible B, the overturned boat. Ismay is shown receiving a "walk of shame" aboard the Carpathia while Lowe personally hands Rose some coffee. Cal enters the steerage area and mistakes another red haired woman for Rose. This explains how Rose knew that Cal was behind her, and made sure he didn't see her. Old Rose also expanding on Cal's fate (his sons fought each other for his remaining assets, "like hyenas"). It includes an extra line from her, comparing herself to a caterpillar becoming a butterfly, before Lewis mentions they couldn't find any record of Jack.
An alternate ending was filmed where Brock, Lewis and Rose's granddaughter catch Rose before she throws the Heart of the Ocean overboard. Instead of trying to stop her, Brock requests to simply hold the jewel for a moment before giving it back to her.
This is a James Cameron film. So the final film's 3 hours long. There is an hour of deleted footage and another hour worth of script that was never filmed. Among the latter, an entirely unrelated subplot about Real Life early film pioneer Daniel Marvin, his wife Mary and his newbrand camera all aboard the Titanic.
The water during filming was deliberately cold, so Leo shouting "Oh shit, this is cold!" is real as well as Kate's gasp when she gets chest-deep in the water. The scene where Jack and Rose are swept away by a rush of water in the hallway is also real.
In the scene where Cal and Rose argue about Jack, Kate's frightened reaction to the meltdown is authenticZane improvised the table flip as revenge for the above example.
Expy: A non-narrative example. The film's score is often described as being reminiscent of the music of Irish singer/musician Enya, in particular the song "My Heart Will Go On". According to several books on the making of the film, this was intentional: Enya recordings were used as temporary tracks and the performer herself (who had some film and TV scoring experience) was invited to compose the final score, but declined. James Horner was reported asked to compose a score in Enya's style. And quite accurately, too: the anthemic music heard when Titanic launches is very similar to Enya's composition "Book of Days".
Australian Jonathan Hyde as English White Star Line Chairman J. Bruce Ismay.
The actor playing Sixth Officer James Moody, Edward Fletcher, is American.
Fake Irish: Victor Garber (Jewish Canadian) as Belfastman Thomas Andrews, who in fact had a brother who became Prime Minister of Northern Ireland.
Fake Nationality: American Danny Nucci as the Italian character, Fabrizionote Though Nucci is in fact Italian on his father's side, and was raised there for several years.
Follow the Leader: Pearl Harbor, which has a similar romance-against-epic-tragedy-of-the-20th-century concept, and, like most following works, has almost no understanding of why it worked here. It works in both directions too—Cameron decided to make Titanic after seeing the 1958 movie A Night to Remember, to the extent that they have a lot of scenes in common.
Font Anachronism: The film features Helvetica on some of the gauges on the ship. Titanic takes place in 1912. Helvetica is invented 45 years later.
Could be the almost identical Akzidenz-Grotesk, invented in 1896.
Genre-Killer: Of the "it's so good nothing else can live up to it" variety. There haven't been any major movies about the Titanic since this one.
Life Imitates Art: In one of the deleted scenes, Brock's manager Bobby tells him that they're over-budget, the partners depending on them are pissed, and that they're in serious danger of getting shut down. Jim Cameron later noted that when he was writing this, he had no idea he would be hearing all these things when the production ran into problems.
Meaningful Release Date: The 3D rerelease was timed to correspond to the centenary of the sinking in 2012. It released on April 6th, four days before the Titanic set sail - most likely to avoid a midweek release, and to capitalize on Easter weekend crowds.
When Jack makes Rose "fly" at the bow, he starts singing the popular 1910 song Come Josephine In My Flying Machine, and she laughs. This is a throwback to a deleted scene that came after Jack brought Rose to a party in steerage. As he accompanied her back to First Class, the two sang Come Josephine.
When Cal finds Rose at the lifeboats, he is disgusted to see her in a poor checkered blanket. In a deleted scene, she got that blanket from a generous couple at steerage, after they broke into the main hall. You see the same steerage couple swimming in the freezing water after the ship goes down.
Lovejoy has a gash on his head as a result of a fight with Jack that was cut from the film.
The Red Stapler: Since this film, passenger ship companies have had to actively stop passengers from doing the "I'm the King of the World" stunt standing on the tip of their ships' bows, since that's a very dangerous thing to do.
Science Marches On: The depiction of the ship sinking was based on CGI models compiled by research and survivor accounts that were accurate at the time of production. A later study commissioned by James Cameron for the 100th anniversary of the sinking indicates that the Titanic probably broke at 23 degrees or so, half of the approximately 45 degrees as depicted in the movie.
The CGI animation the study came up with can be found here.
The movie also made this happen: the scene of the Grand Staircase when it started being flooded led to Titanic scholars changing their theories of how it was destroyed during the sinking.
Jack telling Rose to lie "Over on the bed uh, the couch." was an accidental flub, but James Cameron thought that was natural, so he left it in. You can see Leonardo DiCaprio almost swearing to himself, thinking he's ruined the take, but it comes off as a nervous 20-year-old thinking how much he just embarrassed himself in front of the girl he loves.
During the lunch scene, the line "Freud? Who is he? Is he a passenger?" was an ad lib by Jonathan Hyde.
When Cal tries to force Rose into a lifeboat, she was supposed to jab him with a hairpin. Instead, Kate improvised spitting in Zane's face and the scene was kept in.
The heartbreaking line "Jack! This is where we first met!" was also ad-libbed by Kate Winslet.
Troubled Production: The film cemented Cameron's reputation as Hollywood's biggest Jerkass, so much so that the crew claimed he had a psychotic alter ego named "Noremac Mij". Apart from terrorizing the film's two lead actors (Kate Winslet suffered bruises so impressive that the makeup artists took photos to use for reference later), driving it insanely over budget and schedule and having to deal with cast members who came down sick from a shitload of hours spent in cold water, Cameron and about 50 other guys fell victim to an almost Deadly Prank when a crew member put PCP in their soup, forcing them to spend a night in hospital.
Robert De Niro was offered the role of Captain Smith but turned it down due to a gastrointestinal infection at the time. Michael Caine was also offered the role.
Lindsay Lohan auditioned for the role of Cora Cartmell. Lohan, who was then an unknown and was only 8 years old at the time casting took place, was the top choice for the role. However, Cameron felt that Lohan's fiery red hair would confuse people into thinking she was related to the characters Rose and Ruth, who both had fiery red hair. Alexandrea Owens was cast instead.
Cameron originally offered the part of Thomas Andrews to Lorcan Cranitch, then best-known for the TV series Cracker. Cranitch wasn't interested in committing to Titanic's open-ended filming schedule and turned it down.
There were many different scripted deaths for Fabrizio. One had him swimming to Cal's lifeboat and asking to be let in, saying that it was his destiny to go to America. Cal would then knock him with an oar and sarcastically yell "It's that way!"
In the script, Cal would have found Rose on the Carpathia, only to finally be told off by her and instructed to never seek her again, so that his actions during the sinking would never be revealed.
The Norwegian singer Sissel Kyrkjebø was considered to sing "My Heart Will Go On" before they decided on Celine Dion. Kyrkjebø did, however, provide the One-Woman Wail you hear in the background of the film's theme.
In the original script, "I'm the king of the world" is never uttered. The only dialogue in that scene is Fabrizio mentioning that he can see the Statue of Liberty.
Only the starboard side of the set below the superstructure was fully built and riveted. When it came time to film the scenes in Southampton, everything had to be backwards so it could be easily mirrored in post-production, even down to the buttons on people's clothing.
The engine room for Titanic was filmed aboard the World War II Liberty ship SS Jeremiah O'Brien (a museum ship in San Francisco), since the engine design was almost identical.