Jetpacks don't have brakes. Once you start moving, coming to a stop is very difficult or very harmful. You have to be a highly trained specialist to operate a jetpack at all, while you can gently learn to operate a car.
Flight in general is unforgiving this way. There's only so much practicing you can do under 20 ft and 20 mph.
Airplanes you can at least use simulators and flight instructors who can take control when you mess up; jetpacks you lose any opportunity for a co-pilot, so you probably need good flight simulators you can log hundreds of hours in before strapping in.
