The plane that Frank took from Las Vegas is an Airbus A320 series plane but the plane in New York where he is taken off on a stretcher is a MD-80 series plane.
When Frank visits Rosie at her apartment, after he enters no one closes the door. In a later shot, when Rosie's friend arrives with the baby, she knocks on the now closed door.
In the scene where Frank's kids visit their father in the hospital, Robert's arms shift from crossed in the head-on shots to extended (leaning on the bed frame) in the side-angle shots.
When Frank is visiting his daughter in her fancy office, two guys from Marketing appear to pitch some new advertising campaign. During the pitch camera view switches repeatedly between front and rear. In front view the short guy holds his belt buckle with both hands, in rear view however his hands are hanging down or are at his back.
The telephone lines they keep showing are power lines not telephone lines.
During the film, telephone conversations are heard as if coming from the "wires" on the poles next to the track or road. Long distance telephone lines have been buried below ground in cables and later, fiber optic lines, since the 1950s. The wires shown are electric or signaling wires.
Rosie changes her utensil-holding hand between childhood and adulthood, but this not unheard of.
When Frank takes the train from Chicago to Denver he passes some beautiful scenery, including various desert mesas as well as Glenwood Canyon, both things one would see when approaching Denver via Amtrak from the west, not the east.
Wine is not sold in supermarkets in New York State.
The symphony poster in the movie said "Denver Symphony." The "flashback" poster at the end of the movie says "Northwest Symphony."
When they were first in the limo in Vegas, the car was heading south on LVB, passing the Excalibur on the right. A minute later, the mid-strip hotels were also on the right. This is impossible - unless driving backwards.
When Frank is taken off the plane after his heart attack, he is taken away in an ambulance that said FD NC. While he was scheduled to land in NY, the ambulance was apparently borrowed from another town, probably New Canaan, CT.