As others have pointed out, we have jetpacks today. We've had them since the 1960s. You want to know what the difference is between then and now? Now you have to sign a waiver before you can even strap it on, and the operation time is ~45 seconds at over $90.000 USD as of a 2012 Discovery channel broadcast - in the 60s, it was more like 10-15 seconds.
Don't forget to factor in taking about 10 seconds just to get off the ground, and likely at least that long to bring yourself to a safe landing. We're not using
Heinlein's powered drop pod soldier suits.