The jetpack allows the wearer to fly for short durations, giving them a tactical advantage over others. If the user does not fire the rockets, they will slowly lose altitude. In the base game version the jetpack is only usable in the Siege gametype.
In JA+ mod you can equip and take off jetpack any time you desire by command
jp_allowJetpack must be set to 1 )
To activate the jetpack, jump, then press 'use' while in the air. Holding 'jump' will allow the user to gain altitude, while holding 'crouch' will decrease altitude.
Pressing use again will switch the jetpack off.