Jet Bridge — Passenger Boarding Bridge

Invention and Early History

The passenger boarding bridge traces back to the 1950s search for a way to move passengers between terminal and aircraft without exposing them to weather, engine noise, and the general hazards of the ramp. United Airlines tested an early prototype called the "Air Dock" in 1954, and the first operational version — Lockheed Air Terminal's "Aero-Gangplank," credited to engineer Frank Der Yuen — was installed by United Airlines at Chicago O'Hare in 1958. Before this, boarding meant walking across the tarmac and climbing mobile stairs, an experience still common today at airports and airlines that skip the jet bridge by design.

How a Modern Jet Bridge Works

A modern jet bridge is a telescoping, motorized walkway, one end pivoted at the terminal gate and the other end — the cab — able to extend, retract, raise, lower and rotate to dock precisely against a range of different aircraft door heights and fuselage angles. An operator (increasingly gate agents themselves, using simplified controls, though some airports use dedicated bridge operators) drives the cab into position once the aircraft is parked and chocked. A rubber or accordion-style weather seal closes the gap between the cab and the fuselage, and a leveling mechanism accounts for the aircraft settling slightly as fuel burns off or passengers board.

Types of Boarding Bridges

Most bridges in use today are the standard single-tunnel telescoping type described above, but airport-specific variants exist: apron-drive bridges move along a track parallel to the terminal rather than pivoting from a fixed point, useful where multiple aircraft types and gate positions need to be served from one structure. Dual-level bridges serve aircraft with two boarding doors at different heights — used for the Airbus A380, where separate bridges (or a single dual-bridge unit) can load both decks simultaneously to cut turnaround time. Some older or space-constrained airports use "walk-in" designs anchored mid-bridge with movable ends, historically seen at facilities like the former Hong Kong Kai Tak Airport.

Why Not Every Gate Has One

Jet bridges are expensive to install and maintain, and many low-cost carriers deliberately avoid them — boarding via airstairs at remote stands is faster to turn around in some circumstances, avoids landing/gate fees tied to jet-bridge gates, and lets an airline board from both the front and rear doors simultaneously, which a single jet bridge cannot do. This is a genuine operational trade-off rather than a downgrade: airlines optimizing for fast turnarounds on short-haul routes often prefer stairs specifically because dual-door boarding is faster than a single jet bridge.

Jet Bridges and Turnaround Time

Because boarding and disembarkation speed directly affects how quickly an aircraft can be turned around for its next flight, jet bridge availability, positioning accuracy, and the choice between single or dual-bridge gates are all factors airports and airlines weigh when planning gate assignments — particularly for wide-body aircraft where even a few minutes saved on boarding compounds across a hub's daily schedule.