The plane they are on changes several times throughout the movie. When it is sitting at the gate in Dallas, and while being pushed back from the gate, it is a Boeing 737. When it is shown taxiing out, it is an Airbus A320. Air to air shots are of a Boeing 767, which is also the same as the interior shots all throughout the movie. The 737 and A320 are narrowbodies, while the 767 is a widebody, commonly configured 2-4-2 like the interior in the movie.
When in the plane's bathroom, in an early take Cillian Murphy threw Rachel McAdams so hard against the bathroom wall that he knocked her unconscious. If you look at the shot used in the movie where he throws her against the wall, you can see his hand in her hair protecting her head so he didn't hurt her again. Not a mistake, as he's not trying to knock her out in the film, just rough her up, but worth looking for.