The Jet Pack is a good counter against the Rocket Launcher and Hellfire (and to some degree the Antimatter Jet and the Menacer); being in the air makes it much easier to dodge the shots, and also makes you a much smaller target to Rocket Launcher users who aim for the nearby floors or walls.
The Jet Pack, when combined with a long range weapon (such as the Auto-Rifle), can be a good counter to the Plasma Cannon, as the player can simply float far away in the air, reducing the damage of the Plasma Cannon.
This tool can also be useful when fighting, because opponents find it unnerving to fight against someone in midair. Also, it can be used to get away from a melee if your health is low.
|Acceleration - Berserker Shield - Cloaking Field - Damage Amplifier - Health Recharge - Jet Pack|