Jetpack International's T-73 achieves vertical takeoff with an actual jet engine as opposed to the rocket engines used by the majority of jetpack models. This allows it to have longer flight time (9 minutes as opposed to 30 seconds). Some fighter planes also manage VTOL with a jet engine, the most well-known of which is probably the F-35. Most jets aren't powerful enough to achieve vertical takeoff and rockets are usually required. What is it about jetpacks and fighter plane engines that gives them the extra boost in power? I'm guessing a very powerful compressor to intake enough air even when starting from rest?