You have to be real careful who you bring stuff like that up with, because 99.9% of the people would think you've jumped off the deep end (I don't, but I'm nuts as well).
Of course, if reality were a part of the movie, Tom Hanks would've died in the crash to begin with. I doubt that person could've survived the crash (just try to hold your breath while he is under). I also have my doubts that a plane could've gotten that far off the radar screen (especially FedEX, where you can see if your driver has stopped for a pit stop with your package). They would find the wreckage in a matter of hours, and most likely know the exact spot the plane went down.
For the movies sake, which I enjoyed, it would've been a pretty short movie. Guy yells at a bunch of Russians, jumps on a plane, eats dinner, Jumps on another plane, and dies.