The Answer
Zero Hour!
Here’s plot you’re likely familiar with.
A shell-shocked WW2 fighter pilot Ted Stryker takes a plane ride to persuade his ex to reconcile with him. The pilot, co-pilot, and passengers fall ill from eating bad fish, and Stryker is called upon by a doctor and the stewardess to avert disaster by landing the plane safely. Stryker’s former commander talks him down from the control room.
This is actually the plot of the 1957 film Zero Hour!. Change the name Ted Stryker to Ted Striker and you’ve now got the plot to the 1980 film Airplane!
I had always assumed that Airplane! creators Zucker, Abrahams and Zucker were parodying the Airport movies of the 1970s. While there are definitely some influences from those films, Zero Hour is the obvious source material as you can see in this video below which explains a few more details, but also some scene-by-scene comparisons to show just how directly it was adapted.
Even after watching this video twice, I just realized that Zero Hour! also has the exclamation mark at the end, as Airplane! does.
I must admit that I did think it was a little odd that Striker was a WW2 fighter pilot in a movie set in 1980. Robert Hays was born in 1947, making this exceedingly unlikely.
I also learned recently that the exterior airplane sounds were from a propellor plane rather than a jet as was featured in the movie. It appears likely that this was a nod to the original film!