Real biker gangs were hired in order to get the look of real prisoners for the prison fight scene. It was unknown at the time, but there were four rival gangs in the scene. However, no incidents occurred.
On the day of shooting the 1970s flashback shoot-out, George Kennedy had come down with pneumonia. He was so ill that he couldn't even walk. To make sure the scene was shot, director Peter Segal had Kennedy sit on a bar stool for his entire part in the scene. Notice when Frank meets Ed, Ed never gets up from his stool. When Ed is supposed to leave, leaving Frank alone with Tanya, Kennedy simply just leaned back out of the shot to create the illusion of his character getting up and leaving.
After the credit for the weapons handler, there's a credit for the "concealed weapons handler," Leon Czolgosz. Czolgosz was the man who assassinated U.S. President William McKinley in 1901 by shooting him with a pistol he had concealed in an arm bandage.
The flashback scene from Frank and Jane's wedding was the real ending for The Naked Gun 2½: The Smell of Fear (1991). They didn't use it on that movie, but inserted the scene on this one. At the same time, the scene featuring Frank, Jane, and Frank, Jr. getting to their house was the original ending for this movie, but since the makers thought that the boy that played Frank, Jr. didn't look funny enough, they decided to go with the hospital ending, and used this scene in the middle of the movie.
The "rare" Canary Island Pine is actually one of the most common trees in the world.
Courteney Cox: Appears briefly as one of the five nominees for Best Actress at the Oscar ceremony. The other actresses are named in this movie, but Courtney is not and does not appear in the credits.