Much of the plot of "Airplane!" is taken directly from the 1954 movie "Zero Hour", even down to some of the dialogue! The filmmakers got the idea after seeing an ad for the film on TV when they were taping commercials to parody. They saw the movie as a way to wrap the commercials around as if it were a parody of the late shows on television, but when presenting the idea to a producer, he suggested just parodying the movie itself. Source: Commentary on the "Airplane!" DVD.
The aircraft used in the movie is a Boeing 707. The markings on the aircraft are exactly like the "Trans World Airlines" (TWA) markings of the time. The only difference between the two airlines are the names. If you look at the tail of the plane in the movie you will see the letters "TA" for "Trans America", however, the tail and body lettering in the movie is the same lettering that TWA used on their aircraft at the time. Just add a "W" to that tail and it's all set!
ZAZ wanted the plane to be propellor driven, but Paramount wanted the plane to be a modern jet. The compromise was to use a modern jet for the plane, but all of the sounds were those of a propellor airplane.
When you see an exterior shot of the plane, you can hear the sound of a large propeller aircraft - not a jetliner like its supposed to be. This was a deliberate joke. In fact, the filmmakers wanted a propeller plane, but the studio wouldn't go for it, so the comporomise was the sound.
When the movie is shown on TV there is, of course, some footage removed to make the FCC happy, but unlike most movies this one has added footage that you can only see when shown on TV.
The only one I know shows the pilot calling out the engines as he starts them and then as the engines start they make a piston engine sound, Apparently, this footage was cut from the original movie, but was added to the broadcast verson to get the running time back up. By the way, you will not find this footage on the DVD.
When I saw the original film release, there is a scene missing in which Kareem Abdul-Jabbar becomes violently ill and strips to his Laker's uniform. You see him dragged out in uniform without explanation in later versions.
Two reasons this scene may have been dropped, one is NBA protest over copyright or licensing issues, the other is that the same scene with Peter Graves is funnier and redundant. There were a couple of other scenes I have forgotten over the years. I hate when the film release is cut down for video and scenes lost forever.
On some TV showings, there were additional scenes involving the boy and the girl who likes her coffee black like her men. I don't remember what they said. I believe it was a series of romantic cliches.
In the original 88-minute movie there is a series of jokes about a teenage girl who asks a young man to make love to her before they all die. Then she asks an older man. Then there is a line of men standing in the aisle waiting their turn. Finally she is seen smoking a cigarette next to a horse that also is smoking. The DVD and streaming versions are 87 minutes long and cut all these scenes.