A jet bridge (also termed jetway, gangway, aerobridge/airbridge, air jetty, portal, skybridge or its official industry name passenger boarding bridge (PBB)) is an enclosed, movable connector which most commonly extends from an airport terminal gate to an airplane, and in some instances from a port to a boat or ship, allowing passengers to board and disembark without going outside or being exposed to the elements. Depending on building design, sill heights, fueling positions, and operational requirements, a jet bridge may be fixed or movable, swinging radially and/or extending in length. The jetway was invented by Frank Der Yuen.