As such, jet bridges provide enhanced access to aircraft for passengers with many types of disabilities and mobility impairments, as they may board and disembark without climbing stairs or using a specialized wheelchair lift. Additionally, many models offer leveling devices for the portion of the floor that makes contact with the aircraft this allows passengers to slowly transition from level aircraft floor to sloping jet bridge floor. The cab is provided with an accordion-like canopy, which allows the bridge to dock with aircraft with differing shapes, and provide a nearly weather-proof seal. These motions are controlled by an operator's station in the cab. The cabin, at the end of the loading bridge, may be raised or lowered, extended or retracted, and may pivot, to accommodate aircraft of different sizes. They are often permanently attached at one end by a pivot (or rotunda) to the terminal building and have the ability to swing left or right. Jet bridges provide all-weather dry access to aircraft and enhance the security of terminal operations. The first operational "Aero-Gangplank", as it was dubbed by inventor Lockheed Air Terminal, was installed by United at Chicago's O'Hare Airport in 1958. United Airlines tested an early prototype "Air Dock" in 1954. Mobile staircases or "ramp stairs" are employed at many airports around the world, particularly smaller airports and terminals supporting low cost carriers.
Video of jet bridge being moved to an American Airlines plane at Toronto Pearson International Airport in Mississauga, Ontario, Canadaīefore the introduction of jet bridges, passengers normally boarded an aircraft by walking along the ground-level ramp and climbing a set of movable stairs, or airstairs on aircraft so equipped.