Boarding stairs, sometimes called a boarding ramp, or a gangway in the case of ships,^[1] are devices, designed to safety standards,^[2] which passengers and crew use to board a ship or an aircraft when no built-in stairs are available. Larger aircraft may use one or more fingers attached to the terminal building for passenger boarding, but boarding stairs are used when these are not available or it is impractical or too expensive to use them.^[2]

Boarding stairs must be robust and stable, capable of withstanding adverse weather conditions. They are designed to adapt to the curved shape of the aircraft fuselage to which they must be attached, and to be able to raise and lower them to adjust the upper platform to the height of the aircraft, allowing passengers get on and off from the ground to the aircraft door, thus providing a comfortable and safe way for boarding and disembarking. which is part of the airport infrastructure.^[3]

They are generally mobile stairs, attached to a chassis that is equipped with wheels in order to move them. They can occasionally be pushed by hand, but usually they are pulled by tractors^[4] or are self-propelled, being permanently mounted on a specialized vehicle, a pseudo-van^{[clarification needed]}, with an electric or gasoline engine, which transports the stairs around the airport and places them attached to the side of the aeroplane door.^[5]

Smaller units are generally moved by being towed or pushed, while larger units are self-propelled. Optional features may include canopies, heating, supplemental lighting and a red carpet for VIP passengers; most models have a handrail for added safety. As larger aircraft have door thresholds between about 1.5 m and 6 m (5 ft to 20 ft) off the ground, boarding stairs make it easier for passengers to get on and off comfortably by providing a secure connection between the aircraft doors and the ground, following the rules stipulated by the "Dynamic Regulation System" ^[6]

Today, almost all large airports with modern check-in and boarding rooms predominantly use closed walkways, the so-called fingers, which, although firmly connected to the door, can move in two or three dimensions, being able to adapt in this way, to the doors of the airplane cabin. This allows passengers to board the aircraft directly without disembarking at the airfield during boarding. The first enclosed walkway was introduced by American Airlines in San Francisco in 1959. 1st Class passengers used the so-called "Jet Airwalk",^[7] while the 2nd Class walkway was the "Jetway".^[8] This method of boarding the plane, although it is the most comfortable for the passenger, consumes more resources of the airport, which, consequently, charges the airlines. In order to save costs, some low-cost airlines often forgo this upgrade and use the classic boarding stairs. 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.^[9] The jetway was invented by Frank Der Yuen.^[10]

There is also a type of boarding stairs for ships or yachts, known as a gangway, which provide safe access between the dock or auxiliary boats and the ship. In the case of a yacht, the choice of the most suitable type of boarding ladder will depend on the size of the yacht, the space available on the dock, etc.^[11]

There are different types of boarding stairs:^[12]

• Telescopic boarding stairs: These ladders extend and retract as needed. They are ideal for yachts with different deck heights. They can be manual or electric.
• Fixed walkway ladders: These ladders are permanently attached to the yacht and deploy towards the dock. They are robust and durable, but require storage space on board.
• Folding gangway ladders: These are similar to telescoping ladders, but they fold instead of extending. They are compact and easy to store.
• Rotating boarding stairs: These stairs can be rotated in different directions to suit the position of the yacht in the dock. They are versatile and useful in small spaces.
• Hydraulic gangway ladders: They operate with hydraulic systems and can extend and retract automatically. They are convenient and often found on luxury yachts.
• Carbon or fiberglass walkway ladders: These ladders are lightweight and strong. They are popular on modern yachts due to their elegant design and ease of use.

• 
  Mobile boarding stairs, open without a roof
• 
  Mobile boarding stairs, covered with a roof
• 
  Passenger boarding bridge with "two fingers"

• Power Stow Power Stow - Official website
• TLD Group TLD Group - Official website
• Terberg Aviation Terberg Aviation - Official website
• Mercury GSE Mercury GSE - Official website