External images of the aircraft landing in the beginning of the film are of a Boeing 747. The flight deck shots of what is supposed to be the same aircraft are of a Douglas DC-8 (note the center window).
When Dr. Wentworth is trying to get out of his car he first breaks off the window handle and drops it on the passenger side. Next, he breaks off the door handle, but somehow the window handle is back in place.
When the 747 is landing at the beginning of the movie, the shots are out of order. After a cockpit shot has shown that automatic engine braking (reverse) has occurred (four amber lights at the top center of the instrument panel), a long shot shows the aircraft still in the air. Later, another shot shows the aircraft approaching the gate, but in the next (cockpit) shot the amber lights are still active.
When the huge threatening note comes though the bathroom windows attached to a boulder, the lid of the toilet tank is knocked into a diagonal position. In close-up shots the tank lid is askew, but in long shots the tank lid is undisturbed.
In the shower scene, the showerhead adjustment knob projects straight up out of the top of the showerhead when viewed from outside the shower, but is turned sideways when viewed from inside the shower.
In the shower scene when the bellboy finishes stabbing the doctor with the newspaper he clearly drops the rolled paper on the floor next to him, then the shot shows the folded paper ink running down the drain.
In the scene at the bar of the hotel, the pianist asks Dr. Thorndyke if "B flat" is an okay key to play the song "High Anxiety" in for him to sing to. The song in the movie during that scene actually begins in the key of "A" and then modulates up 1/2 step to the key of "B flat" for the end of the song.
After the nurse falls out the tower and tries to fly away on her broom, when they cut back to everyone in the tower, a broom is seen leaning against the wall. However, there are actually 2 brooms: a broom (with a thick handle) is clearly seen against a wall in the tower. Nurse Diesel has a broom in her left hand (thinner handle) as she enters the tower room, and it clearly remains in her grasp as she falls from the tower. The second broom with the thicker handle remains untouched against the wall of the room.
Toward the end of the "BIRDS" scene when Dr. Thorndyke is sitting in the gardener's shed being showered by the pigeons above him, one gob of the 'mayonnaise and spinach' mixture enters the picture from the left and strikes him on his left shoulder. Who launched this horizontal projectile?
When Dr. Thorndyke goes to his hotel in San Francisco for the convention, he is put on the 17th floor, where the mad bellhop says "you can't get any higher, top floor, we're pretty high," yet it is clearly evident that the hotel has more than 17 floors, both from the lobby looking up and from Dr. Thorndyke's balcony. In actuality, the Hyatt Regency has twenty floors.
When Dr. Wentworth is expressing his desire to leave the Institute to Nurse Diesel, the window from the inside is totally different than the outside, even more so when Nurse Diesel goes to the window to close it.