An armrest assembly for a passenger seat is disclosed. The armrest assembly may be disposed in a stowed, collapsed or passenger configuration where the armrest assembly is of a first length, and also may be disposed in an extended or cargo configuration where the armrest assembly is of a second length that is greater than the first length. Such an armrest assembly may be used to convert all or a portion of a passenger compartment (e.g., of an aircraft) to a cargo compartment by disposing a plurality of armrest assemblies in their respective extended/cargo configuration. Any appropriate cargo may be disposed on/supported by one or more armrest assemblies in their extended/cargo configuration. A free distal end or distal end portion of each armrest assembly in its extended configuration may be anchored to/supported by an appropriate structure, such as an adjacent passenger seat or a bracket(s) attached to a wall.