The AG bike is technically a cheat, not an unlockable vehicle so it isn't treated as one. You activate it by typing "carving" in the main menu.
The unknown craft are the Wipeout ships. Those are only available if you provide the PRM and CMP files within the Wipeout 1 (ALLSH.PRM/CMP) and/or Wipeout 2097(TERRY.PRM/CMP) discs.