(I am hoping the electric jetpack works as intended, otherwise I have to complain)
When you activate hover mode for the electric jetpack, while spacebar is down, you go up slowly, and when let go, you fall slowly.
When you activate hover mode for the fuel jetpack, while spacebar is down, you fall slowly, and when let go, you fall at normal speed.
I think they are supposed to work similarly, and using the first one's control scheme.