Continuity mistake: In the scene where Fletcher is in his office and he's trying to write that the pen isn't blue, he swipes everything from his desk and there's then an overhead shot showing the only thing left on his desk is a small piece of white paper on the right hand side. A few seconds later the piece of paper has disappeared and has instead been replaced by what looks like a drinking straw.
Continuity mistake: When Fletcher moves underneath the wing of the plane on his flight of stairs, another plane is seen in front of him. It disappears when the pilot sees the shoe land on the windscreen. There is also no sign of the barrier and luggage area that he crashes into a few seconds later.