I saw the jetpack flying around inside the Astrodome in 1965, it was impressive then and still is.
“Jet Pack Perfection
In 1965 when the Astrodome opened in Texas, the theme was all space: the Countdown Cafeteria, the comely “Spacette” hostesses, the team name, of course, and the spacesuited guy blasting off and soaring over the infield in a jet pack.”
Those early jet packs were only good for 25 - 30 seconds of flight time.