Character mistake: It's all very heroic and manly but the effort put into dragging the Phoenix into its takeoff position once the engine is started is totally wasted. Townes and A.J. are both experienced pilots and Elliott is supposedly a genius aeronautical engineer - they must surely be aware that the engine power required to taxi an aircraft is trivial compared to that required to lift it into the air. Even taking into account the drag of the skids and wheels, if that engine cannot propel the aircraft at a few kilometers an hour on the ground it cannot propel it to take off speed, nor keep it up once airborne. They are not there to steer the aircraft - they are taking the strain of the whole weight of the air-frame, dragging it into place, and the energy input of eight exhausted, underfed people would add nothing to the contribution of a 2500 bhp aircraft engine in moving the Phoenix. They are not trying conserve fuel - they had enough fuel for an extended flight with both engines at full throttle, so they have easily enough to run one engine throttled back to reduce stress on the air-frame, which they say they are going to do.
Character mistake: When Arthur Weasley takes Harry aside in The Leaky Cauldron to warn him about Sirius Black, he says, "13 years ago, when you stopped.... You-Know-Who...Black lost everything." Harry is 13 yrs. old in Prisoner of Azkaban and was a 1 yr. old when he stopped Voldemort. Hence, Harry stopped Voldemort 12 yrs. ago, and not 13! Harry turns 11 just before school starts in Philosopher's Stone, turns 12 before school in Chamber of Secrets and turns 13 yrs. old before school in Prisoner of Azkaban. Just an aside, the last digit of Harry's age always coincides with Harry's year at Hogwarts. So, he's 13 in his 3rd year at Hogwarts, which is entitled Prisoner of Azkaban. (00:17:50)
Character mistake: When Jack arrives in New York he's right next to the Statue of Liberty. However when he reaches the library he comes from the East River and walks west. That is a pretty big detour around the southeastern corner of Manhattan, instead of taking the direct route. (01:47:00 - 01:48:20)
Suggested correction: Easier to walk in an open area and have a short distance walking between buildings rather than walking through the city where the terrain may not be the best even with the snow/ice.
Character mistake: After the robots first attack New York City, a series of newspapers is shown. One of the headlines in the French one reads "La Tour Eiffeil est détruite". The proper spelling is "Eiffel" (00:15:55)
Character mistake: Nick states that Wall Street was originally a wall (correct) built to defend against the British (incorrect). The original wall was a wooden palisade built in the 16th Century to defend the Dutch colonists against invading natives and to prevent livestock from wandering uptown.
Character mistake: The name on the sign of the pub/private members club of the Manchester United fans is spelt incorrectly: It should read "The Feisty Goat" but Feisty is misspelled on the sign as "Fiesty" instead.
Character mistake: The mother is supposed to be American, but she speaks in her native Australian accent near the end when she says, "I don't think I can take anymore of this" upon finding out that Pita may be alive.
Character mistake: When we first see Sophie her body was slumped over (the spell to make her old) but later on in the movie, her back magically seems fine. (00:00:01 - 01:50:00)
Character mistake: When Marie joins Bourne in the bathroom while he's getting medicine, Marie says he's burning up. She gets a washcloth, wets it and dabs Bourne's neck. She only had what couldn't have any more than a tablespoon of water and dabbled it less than a few seconds. It couldn't have had any effect on someone who was burning up.
Character mistake: Tom Manning criticises Hellboy for using a lighter, (correctly) telling him to use a wooden match instead. But he then lights a match and immediately puts it to the cigar, instead of waiting for the sulphur to burn off and using a pure wood-fuelled flame to light it. He's not as well informed as he thinks.