It’s true that despite a late-career flourish in comedy, Nielsen was actually cast in AIRPLANE! because of his history as a serious character actor. Nielsen played the role straight and got many of the funniest and most memorable lines in the movie (“I am serious. And don’t call me Shirley.”)
His work in AIRPLANE! would reteam him with the creative team affectionately known as ZAZ (Zucker Abrams Zucker) for the TV series “Police Squad.” It was so ahead of its time, it might still be ahead of its time and was sadly cancelled after just six episodes. Six years after the cancellation, ZAZ and Nielsen collaborated on a big-screen adaptation and THE NAKED GUN was born. It spawned two sequels (the first almost as good as the original and the third, not nearly as good as the previous two) and launched Nielsen as an unlikely comic star.
He would go on to make a ton of comedies after the NAKED GUN series and sadly none of them were of the commercial or critical success (in fact, most of them were terrible). But Nielsen gave movies he knew were crap 110% anyway and it was impossible to dislike him, even in a terrible movie.
If you’ve never seen them, go watch the NAKED GUN movies again and especially the “Police Squad” episodes. And if you’ve seen them all as many times as I have, go watch them again and enjoy a great actor at work.