"Flight Plan"

Yesterday I watched the movie "Flight Plan." When I saw the advertisement about the movie on TV, I thought it was interesting and I wanted to see it. One of my friends told me that its story was not realistic and not interesting. Though actually I did not care about his opinion then, I wanted to check out his saying.
The story is that a woman's daughter is kidnapped on an airplane by one of passengers. Then, the woman tries to find her. As to the story, there are something unreal; for instance, the crews on the airplane say, "We have never seen your daughter." However, does it really happen? Some of the crews are supposed to see the passengers at the entrance of the airplane. Though I still have a question about the story, I enjoyed that movie anyway!