The Jetpack allows the user to fly continuously by holding the jump key until all fuel in the Jetpack is exhausted. The Electric Jetpack is slightly more expensive materials-wise, but it functions on electricity instead of fuel.
The Jetpack is also equipped with a Hover Mode, which is activated by pressing the M button and spacebar. The Hover Mode will cause the player to slowly descend, and consumes much less fuel than the normal mode. The Electric Jetpack's "hover mode" will also slowly rise while holding jump and slowly descend when you let go, making it much less awkward to use.
The standard jetpack is also more powerful than its electric equivalent. In the overworld, the Jetpack will take you up to 244 blocks, while the Electric will only take you up to 185, and in the Nether, the jetpack will take you up to 116, while the electric will only take you up to 85. You will however take fall damage, so wear Rubber Boots, Nano Boots, or Quantum Boots when flying.
The Jetpack can use Biofuel Cells, Coalfuel Cells, and Fuel as sources of power. If you wish to use either Cell, you must recharge the jetpack with a Canning Machine. 18 Biofuel Cells or 6 Coalfuel cells will charge the jetpack to about 90% full capacity. If filled with Coalfuel, the jetpack will last slightly longer, but both types of cell last approximately 55-60 seconds.