A cargo unit for storage in a cargo hold of an aircraft including a housing and a storage rack arrangement, the housing enclosing the storage rack arrangement and including a transport opening. The cargo unit is connectable to a transport arrangement operable for removing objects from the storage rack arrangement and placing objects in the storage rack arrangement through the transport opening when the cargo unit is arranged in an operating position. The cargo unit includes a transport cover movable between a closed position where the transport cover closes the transport opening and an opened position where the transport opening is not covered by the transport cover. The transport cover is adapted to be only movable from its closed position to its opened position after engagement with a transport arrangement. A lower deck catering system including a cargo unit and a transport arrangement is described.