We assured him we wouldn't count this brief comedy experience against him. But when he read the Airplane! script, he "got" its unconventional nature and offbeat style. We heard later that he told his agent, "Take whatever they offer; I'd pay them to do this."
Arguably the best role was that of Dr. Rumack, played by the guy no one wanted or ever suspected would be funny, much less go on to have a second career starring in feature films as a goofball comic. Leslie was great in the role because he never "winked" — let on that he knew he was in a comedy. This was essential to the style, and Leslie had a natural instinct for it.