Other mistake: Several actors/props/areas etc. are well known in this area to be flipped. For example, Billy Zane, who plays "Cal" in this film is right-handed, yet in some areas he uses his left-hand when it's not dominating and natural. (Noticeably, when he is chasing Jack Dawson down the grand stairs, he is holding his gun in his left hand, when it would make more sense to hold his gun in his right hand.) (02:13:00)
Other mistake: The ship is down by the bow about 30°. There follow scenes in which people make their way through flooded passageways. The water is chest-high, but level.
Other mistake: After the "flying" scene, the story cuts back to real time. When it starts to transition back to the flashback, the camera zooms in on a television screen with the fireplace in it. This screen is 1) also used in the beginning of the movie 2) impossible, seeing how there was only one ROV in that room, and it shows the ROV in it. (00:06:15 - 01:20:10)
Other mistake: After Jack and Rose are "done" in the cargo hold, they come out onto the bow of the ship laughing. Whilst the door they used to get onto the bow does lead to the cargo hold, inside you have to go down a flight of stairs and are greeted by a cast iron hydraulic door which can't be opened from inside the cargo hold, and would close automatically if the control wheel wasn't being held. The only way they would have been able to get out is by running back through the boiler rooms.
Other mistake: In the scene where Rose is sitting in front of her vanity mirror after Jack saves her life, Cal bestows upon her the 16-carat Heart of the Ocean necklace. He drapes the necklace around her neck but never actually fastens it (the camera's on him the whole time), yet it stays in place even as Rose touches the diamond and runs her fingers across the chain. A 16-carat diamond would slide right off someone's neck if it were not properly fastened.