From the Super Mario Wiki
soaring in the room in the bottom of the screen.
Jetpack Guys are Black Shy Guys hovering about via the utilization of a jetpack; they are found solely in the game Mario vs. Donkey Kong 2: March of the Minis, where they only appear in the Lava Dome. A Mini Mario can ride them, however if one touches the fire from the jetpack, the Mini Mario will be burned. If the Jetpack Guy is on ground that is directly below it, it will walk like normal Mini Shy Guys until it gets off of the ground by walking off the ground.