The jumpseat (the extra seat in the cockpit or cabin) is strictly regulated and is generally reserved for specific professional individuals authorized by the airline and government regulations. In the United States, under FAA Part 121 rules, this typically includes the airline's own crew members, FAA inspectors performing official duties, and pilots from other airlines that have a "jumpseat agreement" with the operating carrier (often verified through the CASS security system). In some cases, airline dispatchers or air traffic controllers on approved training missions may also be granted access. The "Pilot in Command" (the Captain) always has the final authority to refuse jumpseat access to anyone for safety or security reasons. Passengers, regardless of their status or frequent flyer level, are never allowed to sit in a cockpit jumpseat. For cabin jumpseats, these are strictly for off-duty flight attendants or crew members when all passenger seats are full, provided they meet the airline's specific safety and training criteria.