Carl Reiner discusses his scenes in It's a Mad, Mad, Mad, Mad World.
What Mr. Reiner neglects to mention is that the dangerous scene he describes — where the plane allegedly flew so close to him that he could touch it — is not in the finished film. With one possible exception, all of Reiner's scenes in the movie were shot on a soundstage with the airplane no closer to him than on a rear-screen projection. There's one distant shot at the actual airfield that might be Reiner or it might be a stunt double and the airplane does not come near this person.
Which is not to say Carl Reiner was fibbing. Apparently, he had to do some scenes over because of film being damaged in the processing stage. I've never been able to quite get to the bottom of what happened here. It sounds like they filmed a more elaborate scene on location with an actual control tower at an airfield being buzzed by the plane and with Reiner and Ford and perhaps others actually up on the tower, alternating with stunt doubles.
There's an existing still of Reiner and Paul Ford that shows Ford dangling from the tower in a set-up that's not in the film. It looks like something that was built on a soundstage to do closeups of them for insertion into the location footage. Then (I'm speculating here) most of the location footage was lost so they used only a small bit of it in conjunction with scenes done in the control tower set on the soundstage. Or something. Anyway, here's Carl Reiner. Maybe someone who sees him can ask him to elaborate…