Tomorrowland (film) 101
Frank's Prototype Jetpack is a jetpack that frank made back when he was a kid & hoped to submit it to the 1964 New York World's Fair's Hall of Invention, hoping the transport-device would be of use for anyone in the near future.

At first his jetpack was limited in fuel & was able to emit intense firepower when activated but could not control direction, nor allow used to fly upwards instantly.

Later on after Athena granted Frank access to Tomorrowland via the 1964 worlds fair vintage pin, a robot whom was expunging nearby towers and walkways spontaneously decided to fix & improve the jetpack, thus allowing the results of usage to be effective and approved to used in Tomorrowland. eventually this allowed the scientists of Plus Ultra develop the primary current and model of the jetpack as seen in Casey's vision of Tomorrowland.