There's a certain type of movie that you go to just to see how it ends. The advertising promotes the premise of it, piquing your interest enough so that you want to see how the problem that has been thrown at you gets resolved, or to find out what Rosebud means. One such film is Robert Schwentke's Flightplan, starring Jodie Foster as a woman who, as I'm sure you know if you've seen any marketing materials for this movie at all, somehow manages to lose her daughter in the middle of a transatlantic flight. (Although it's a flight from Germany to New York, everyone on the plane is American, all the passengers and crew, except for a handful of Arabs. I don't think there was a single German on board.)
So you watch this movie to find out, OK, what happened to the little girl? No right-thinking moviegoer would tell you, because that would spoil the ending, and the studio is clearly banking on this kind of reticence to spill the beans. If you think about it, they don't even really have to come up with an entirely plausible scenario for the girl's disappearance, because people who've already seen it will be reluctant to tell you what happens. Even if it's no good. I watched Vanilla Sky all the way through to its preposterous ending, but I'm still not going to tell you what happens at the end, because that would be unsporting of me.
The upshot is that Flightplan has a pretty nifty first half, with Foster becoming increasingly panicked about her little girl, and the crew and other passengers being at first sympathetic and then suspicious of her, but as soon as the reason for the daughter's disappearance is hinted at, then revealed to Foster, it's a total letdown. I won't say anything more than it's the most ludicrously complicated extortion scheme in history. But I will say that if you want to watch this flim, don't pay much attention to the plot.