Well, I watched Flightplan for free, as we have a bit of an office swap going because two people, myself included, are addicted to movies and like to watch bunches. I'll watch anything, but I'm pretty picky about liking something.
This movie had some tension and suspense, but it was altogether predictable. And somewhat beyond belief - in order to render the plot plausible, an airplane had to be invented that seats 440 people on two levels (kind of like a double decker). It would have a lounge for drinks and a first class area that seats people in large lounge chairs. You would also be able to crawl around the mechanical parts of the plane, even mid-flight.
It would also have to contain an in-flight conspiracy.
I wanted to watch it because I like Jodie Foster, but this movie is mere popcorn fluff and not very good popcorn fluff at that.
The test: will she be buying it? My answer: a solid no.