Once upon a time Tomorrowland did a Jet Pack demonstration. I remember seeing this when I was a little kid. I was very happy to find a short video of the Jet Pack at Disney Frontier who found it at Daily Motion.
One thing I remember is that it was LOUD!!! Look at the video, when the Jet Pack Man takes off, first thing you'll see is a kid plugging his ears. Every crowd shot has people plugging their ears. Seeing the man fly was amazing, spectacular, but it was loud, a loud screeching howling loud.
Here's the embed from Daily Motion, posted by an obvious philanthropist named donaldtheduckie
I always wondered why the Jet Pack demonstration didn't last long. Even today it would be a spectacular show. I think it must have been the noise. It was just too loud to keep as an attraction.
Yet, this is the sort of thing that Tomorrowland is for. Today there's not much comparable. The closest I can think of now is the Asimo robot show in Innoventions where the Honda humanoild robot, Asimo, is shown off.