Second Unit Director John Jordan refused to wear a harness during a bomber scene. While giving a hand signal to another airplane from the tail gunner position in the camera plane, he lost his grip and fell 4000 feet to his death.
While on a tirade in his office, Maj. Major walks past a framed photo of Franklin D. Roosevelt. In a continuous shot, he paces around his office, and when he passes the picture again, it is of Winston Churchill, as he makes one more round of his office and grabs the fake mustache out of his filing cabinet, the photo has changed to that of Joseph Stalin.
The film has one of the longest, most complex uninterrupted scenes ever made. In the scene, where two actors talking against a background, 16 of the 17 planes, four groups of four aircraft, took off at the same time. As the scene progresses, the actors entered a building and the same planes were seen through the window, climbing into formation. The problem was, for every take, the production manager has to call the planes back and made to take off again for every take of the particular scene. This was done four times.
This is the first American film to show an actor on the toilet - Martin Balsam, playing opposite Anthony Perkins. Ten years earlier, the first American film to show a toilet was Psycho (1960), starring Martin Balsam and Anthony Perkins.
Director Mike Nichols wanted 36 B-25s to create the big Army Air Force base, but the budget couldn't stretch to more than 17 flyable Mitchells. An additional non-flyable hulk was acquired in Mexico, made barely ferry-able and flown with landing gear down to location, only to be burned and destroyed in the landing crash scene. The wreck was then buried in the ground next to the runway, where it remains to this day.
In the scene where Yossarian (Alan Arkin) is prevented from following Luciana (Olimpia Carlisi) by a policeman directing traffic who gives him a "sorry about that gesture" after stopping him, the officer is played by Buck Henry, who both wrote the screenplay and played Lt. Col. Korn in the movie. In the director's commentary, Mike Nichols said the actor he had hired for the scene wasn't getting the gesture right so he asked Henry to put on the policeman's uniform and do it instead, which the director said he did "beautifully". After the scene cuts to the passing convoy and swings back to the policeman, he's being played by the original actor and not Buck. The director called this quick cameo by Henry "something that nobody knows".
Since shooting took longer than planned, Art Garfunkel wasn't able to make it back to New York in time to start creating harmonies for and recording the Simon & Garfunkel album "Bridge Over Troubled Water". Angered by the delay, Paul Simon wrote the track "The Only Living Boy in New York" about the incident. The lyrics "Tom, get your plane right on time / I know your part'll go fine / Fly down to Mexico" were a thinly veiled attack aimed at Garfunkel (who was "Tom" of Simon & Garfunkel's earlier incarnation, Tom & Jerry), leaving Simon alone in New York to prepare and produce the bulk of the album himself.
The island of Pianosa actually exists 8 miles south of Elba in the Mediterranean Sea but is very small and could not possibly have supported the military installation depicted. This is pointed out by Joseph Heller as a foreword in the novel.
Stacy Keach was originally cast as Col. Cathcart when shooting started, but things did not work out, and Charles Grodin (who had already been cast as Capt. Aarfy Aardvark) was asked to take over. As the part was written for an older man, old-age make-up was experimented with for a few days, until it was decided to cast Martin Balsam instead, and Grodin returned to his original part.
According to his book, "Kiss Me Like A Stranger", Gene Wilder was the original choice for Lt. Milo Minderbinder, but he turned the role down, citing creative differences, and instead accepted the dual role he plays in Start the Revolution Without Me (1970).
The squadron patch on Yossarian's leather A-2 flight jacket - a female nude riding a descending bomb, hurling a bolt of lightning - was the actual patch of Joseph Heller's 488th Bombardment Squadron (Medium), one of four B-25 squadrons (the others being the 486th, 487th, and 489th) in the 340th Bombardment Group (Medium) during World War II.
The chaplain character was renamed in the screenplay as A T Tappman apparently to create embarrassment for the character when giving his name. This name is now used in US versions of the book. The original name R O Shipman persists in UK versions of the novel
Stacy Keach was fired by Mike Nichols and replaced by Martin Balsam in the role of Col. Cathcart. Coincidentally he was also replaced in another Joseph Heller work, the play "We Bombed in New Haven", which started out as a dramatization of "Catch-22". Keach, who originated the role of Capt. Starkey in the play at the Yale Repertory Theatre, was replaced by Jason Robards when it transitioned to Broadway.
Director Mike Nichols originally asked Bob Balaban read for the role of Milo Mindbender, ultimately played by Jon Voight. However, after hearing him, he changed his mind and thought Balaban perfect for the Captain Orr.
When Richard Lester was asked to direct , he had just completed " A Funny Thing Happened on the Way to the Forum " in Spain on the crumbling Samuel Bronston backlot. He considered using his main lead Zero Mostel as Milo.
In "Catch-22" Jack Gilford who plays "Doc Daneeka" convinces Captain Yossarian to pretend to be dying son of a family that traveled from the US to say goodbye before he dies. In "A Funny Thing Happened on the Way to the Forum", Zero Mostel convinces Jack Gilford who plays the male slave "Hysterium" to pretend to be the corpse of the bride "Philia" to "Captain Milos Gloriosus" so that he can say goodbye to his "bride"..
Yossarian refuses to bomb Ferrara because it has no strategic value. On August 23, 1944, Allies bombed Ferrara due to a synthetic rubber plant in the town. There was no reason why any characters in the story would know about the plant, however.
The trivia item below may give away important plot points.
The popular scene of Hungry Joe being cut in two by the airplane and falling into the water was done in two steps. (1) A plane runs into a breakaway dummy that was rigged to spray blood. After a cutaway, the second shot shows an actor or stuntman in front of the sky, holding a mirror in front of him angled to reflect more sky to match what is in back of him, making the top part of his body disappear. He then falls backward into the water making the trick become visible to the camera. Albert Whitlock did the post-production work and rotoscope-matted in more water and horizon around the legs and waist to hide the mirror and top part of the body when it was exposed (look for the patch of slightly different colored water that appears and disappears as the legs fall in). In the commentary Mike Nichols remembers the part about using the mirror but was unaware of, or forgot about, the post-production finishing of the scene.