Kareem Abdul-Jabbar plays a pilot mistaken for Kareem who actually is Abdul-Jabbar, and admits as much when criticized for his lack of effort in the NBA by a young passenger. As he is later dragged unconscious from the cockpit, he's wearing Kareem's goggles, Lakers shorts and sneakers.
Robert Stack, forgetting that he's not playing Eliot Ness:
Air Traffic Controller: Captain, maybe we oughtta turn on the search lights now!
Kramer: No ... that's just what they'll be expecting us to do ...
Blooper: As Ted meets Elaine in the airport corridor, you can see a crewman letting out cable off to the left. The Zuckers acknowledge this in the DVD Commentary.
There's also one in the dance scene, also mentioned in the DVD Commentary: when Striker does a backflip into the crowd, you can see his actor, Robert Hays, off to the side, very obviously waiting for his cue to jump back in to replace his stunt double. His head is fairly visible off to the right.
Executive Meddling: The studio wouldn't let the producers use a propeller plane as the airliner, so the producers gave the jet a propeller plane sound instead.
Genre-Killer: Arguably killed off the whole disaster movie genre for a decade or so by making audiences unable to take them seriously anymore.
That bit player with a handful of lines in the control tower? It's Mike!
Hey, It's That Voice!: The Red Zone-White Zone people on the public address system at LAX were played by the people who actually recorded the public address announcements at LAX.
Robert Hays later went on to voice Iron Man in the 90's Marvel cartoons.
The little girl who likes her coffee black (like her men) was the voice of Penny in Disney's The Rescuers
Money, Dear Boy: Kareem Abdul-Jabbar's salary paid for an expensive rug he wished to purchase.
Playing Against Type: Leslie Nielsen, Lloyd Bridges, Robert Stack and Peter Graves (all serious dramatic actors), doing comedy. In the case of Nielsen, this role redefined his career, and would become his default shtick for the rest of his life. Bridges also briefly became a comedic actor before his death in 1998.
Playing with Character Type: It's surprising to think of it now, but Nielsen's role in the film was based entirely upon playing his established persona of studly, stoic heroes for laughs rather than drama. The gambit was so successful that the term Leslie Nielsen Syndrome came into existence.
Throw It In: Stewardess Randy was supposed to tell the disembarking passengers things like "Watch your step!" and "Be careful!" as they stepped onto the emergency exit slide. However, in an early take, actress Lorna Patterson unexpectedly got all the passengers to crack up by offering each of them a cheery, "Thank you for flying TransAmerican! Have a nice day!" The script was changed accordingly.
Leslie Nielsen Syndrome: This was the film that launched Nielsen's comedy career. Interestingly, this seems to be intentional. The filmmakers deliberately cast serious actors instead of comedians, thus most of the humor was delivered completely deadpan. And it works!
Pete Rose was the original choice of sports-star casting (per DVD commentary). What are the odds?
David Letterman auditioned for the role of Ted. Jerry Zucker brought the audition tape on Late Night once as a prank.
The newspaper boy who "Chews off own foot" was one of the Zuckers' nephews. The DVD extras say one of them called and asked for the youth's school picture. He gave it to them, not knowing why, only to see it in the movie later.
The aircraft that's the titular star of this film is a Boeing 707, the first successful commercial jet airliner not to break in half in mid-air.
The surfing nun on the cover of "Nun's Life" was actually Jim Zucker.
The radio station was named "WZAZ" as a reference to Zucker, Abrahams, and Zucker (ZAZ), the movie's producers.
Special effects wizard Rob Bottin did Dr. Rumack's nose-growing scene when he lies to the passengers, he was uncredited, he later used the same technique for the werewolf transformations in The Howling.
Otto, the inflatable auto pilot, survived the film's production, and was stored in Jerry Zucker's garage until finally disintegrating.