Harry Dean Stanton played the blind old man with the cane in the film. He is Jack Nicholson's best friend, and was cast as the old man at Nicholson's suggestion.
Buddy picks up a golf club and a baseball bat before choosing the baseball bat to smash the window of the Lexus. In 1994, Jack Nicholson was cited for smashing a man's window with a golf club in a bout of rage.
When Dave and Dr. Rydell sit in the plane, we see a middle row of seats (i.e. two aisles). The exterior view of the plane shows a Boeing 737 which doesn't have a middle row.