In one of Ted's war flashbacks, a Visa credit card can be seen. It has been 6 years since Ted last flew, meaning this flashback takes place in 1973/1974 at the earliest. At this point in time, Visa was still called by its original name, BankAmeriCard.
When Rex Kramer first enters the airport, he is approached by numerous solicitors who Kramer then proceeds to rough up. The solicitors explain their various causes just before they are assaulted. However it is clear to see that none of them are talking.
During the fight between the two Girl Scouts at the Magumbo Bar, one girl scout is thrown across the bar and into the jukebox. When her head hits the jukebox window, the sound of shattering glass is heard, but it's clear that there is no glass in the window frame.
At the Mayo clinic with the beating heart on the surgeon's desk, although a heartbeat sound has been overdubbed, underneath that you can hear the little motor inside the heart making it pulsate. This noise is absent in the next shot which shows the heart bouncing around in front of the surgeon's face.
When the orderlies get out of the ambulance to take out the gurney with the sick girl on it, one of them almost trips over his own feet as he's opening the back doors of the ambulance (the blonde one, to the right).
After Elaine lets go of Ted in the dance floor, he somersaults into the audience, quickly gets up and runs back to the dance floor. But while "Ted" (the stuntman) is somersaulting, the real Ted (Robert Hays) is visible in the background.
During the opening montage when certain principal characters are introduced, Joey (the little boy) can be seen in the far background carrying a brown bag in the shot with the Hari Krishnas. A few seconds later we see him getting out of a car with his parents and luggage.
One exterior shot as the plane is landing shows the silhouette of a Boeing 727, noted by the lack of engines on the wings and the two wheels (instead of the four that a 707, which other external shots show the plane as being, would have) on one "main" landing gear assembly. The shot at the very end (where the words "THE END" come up) also shows a 727.
When the plane lands, the landing gear collapses and the plane is on its belly when the passengers disembark. Later, when Ted and Elaine are kissing next to the plane, it is sitting on landing gear which is intact.
During the 747-through-the-window gag, the plane is originally shown to be in period TWA colors, before it is misdirected. However, when it plows through the window, it has the fictional Trans American colors. Most obviously the red stripes now wrap all the way around the nose and the black anti-glare patch is missing from beneath the cockpit windshield.
When he first begins to tell his story to the old lady there is a seatcover between the back of the two seats they are sitting on and the upholstery on both seats is the same. at the end of the story, the seat upholstery is different on both seats and the center seatcover is missing. The upholstery is the same and the center seatback cover is back however a bit later in the film when Ted is sitting next to Elaine.
When Striker unlocks the autopilot the plane takes a deep nose dive and the next scene is of the altimeter whirling around and around. In the same scene, however, the "flight level indicator" next to the altimeter does not show the plane descending at a steep angle. The next scene does show the Flight level indicator finally coming to a level plane.
In the beginning when Striker pulls up in his taxi the available light on top is lit and then goes out when he opens the door, the light on cabs do not go out until the flag on the meter is dropped which did not occur until Ted reached back through the passenger side window.
Ted Striker throws a full glass of drink over his shirt and soaks it. The scene cuts away to the cockpit and then back to Striker (with the Sikh dousing himself in gasoline) and his shirt is dry again.
The plane is flying on a path that starts on the west coast and heads for Chicago, implying that the plane most likely starts in California or somewhere near there. However, the airport where the flight starts and the one where the plane lands are clearly the same airport.
The main plot point in this movie is that the entire cockpit crew is incapacitated as a result of food poisoning from them all eating the fish served as one of the choices for the in-flight meal. However, FAA regulations at the time prohibited both pilots from eating the same meal, specifically to prevent problems like this. One of the pilots should have ordered the steak.
According to the dialogue, the airplane is supposed to land on runway 9 (niner), but the number 30 is clearly visible on the runway's threshold as the plane lands. There is no runway 30 at Chicago O'Hare airport.
Ted flips a switch after saying, "This must turn on the landing lights," and puts the plane into a nosedive, but the shot showing him turning the switch off is obviously on the radio as it has markings of "FREQ" (frequency) and "KC" (kilocycles). Flipping a switch on a radio won't send a plane into a nosedive. Additionally, the radio is too old for a 1980s aircraft because the frequency displayed is 1710 KHZ, which is an aircraft frequency long before 1980, when VHF frequencies would be used.
Although the plane clearly has jet engines, the engine noise heard inside the cabin throughout the film is of a piston-engined propeller plane. This engine noise is taken from the film Zero Hour! and is a long-running gag: Airplane! is a spoof of disaster films such as Zero Hour and Airport.
Despite what Ted Striker hears in his interior monologue, Pedro Borbon and Manny Mota were never on the same roster, so Mota could not have pinch hit for Borbon. This is simply a case of someone imagining what they think would be really cool instead of an actual case of someone recalling something that happened.
When the captain notifies Chicago of the emergency, he said nothing about food poisoning, however, the air traffic controller orders all meal services canceled. This could simply be because the character never did like the food on meal services, a way to comment on how lousy airline food really is, and not because of the food poisoning on the aircraft.
The model airplane that the pilots give to the young boy who tours the cockpit is not the same kind of plane that they are flying on. The model is a 727, the plane being used is a 707. The pilot never said that it was a model of the plane that they were flying.
On the phone, McCroskey orders all food service out of LA to be halted. However, no one had told him that the passengers were becoming sick due to food poisoning, so he would have no reason to halt the food service at that point in time.
When the two "Girl Scouts" are fighting, one is thrown over a railing and smashes a table. The fight continues, the other girl gets kicked backwards and out of frame, at which point she clearly bumps into the camera, causing it to wobble.
At the airport, when Oveur gets a call about the "transplantation-girl" (with the white/red/black phones), after he picks up the wrong phone, you can clearly hear Nancy Hansen (the script supervisor) laughing in the background.
In the scene where Dr. Rumak is treating the sick female passenger, he is removing eggs from her mouth. In one shot where he removes and egg, cracks it and a little bird flies away, the woman is startled and in her half-open mouth you can clearly see that an egg is already there, making it obvious that she was releasing the same egg time and again; equally obviously, then, the doctor was picking up additional eggs from underneath the tray table.