When people scan their boarding passes and wait in the queue to get onto a commercial plane they usually aren’t thinking about the logistics of such a mundane sequence. As people shuffle down the jetway and onto their flight, they are thinking about how they’re going to stow their carry on or where their seat is. They aren’t think about what side of the plane they are entering. It is on the left side of the aircraft. People always enter planes from the left side.
This doesn’t seem like a remarkable fact until you realize that this is the same, no matter whether you are getting on a flight in Madison, Wisconsin, or Tokyo, Japan. In every airport in the world, people shuffle onto their flights on the left side. But why? Why do people board planes from the left? The answer to that question dates back to the Age of Sail and ancient maritime traditions.
Anyone who has spent any time on boats and ships knows that mariners like to use the words starboard and port for right and left, respectively. Starboard is a term that comes from Old English, which means steering side. Port is called so because it was the side of the boat that always docked in port. Ships always tied up with their left sides secured to the dock. This way, no matter what port you sailed into, everyone was on the same page as to how docking, loading, and unloading would go.
People board aircraft from the left because they boarded ships from the left in an era when people sailed far more than they flew. In fact, the flying industry has taken many cues from the old nautical world. (Aeronautical, rudder, and cockpit are all words with maritime origins in the commercial airline space.) When it came time to design planes and airports, engineers reverted to the old habit of large vessels being secured from the left.
Before jetways were invented and people loaded on the tarmac via steps, they still boarded on the left. This is because the pilot used to sit on the left of the plane, similar to a car, and would peer out the window to judge distances between the wing and the terminal to ensure that they were parked properly. The pilot would pull in, with the left of the plane closest to the terminal, and people would file out and then get on via that same side.
Planes need to be loaded from the same side for a number of reasons. First, having everyone board on the same side of the aircraft, no matter the airport, offers standardization that helps pilots fly into unfamiliar airports. It would be confusing and add a layer of uncertainty if pilots had to remember if they were landing in an airport that boards on the right or the left.
Boarding from the same side also keeps the ground crew and passengers separate. It would be unsafe for the ground crew to fuel the plane, load the bags, and check the plane in the midst of passengers. Passengers and flight crew deal with the left side of the plane, while the ground crew deals with the right side of the plane. This keeps everyone separate and enhances safety.
For safety, logistics, and efficiency, planes have to be loaded in the same way every time. A side had to be chosen as the boarding side, and the left was picked due to the fact that ships have always boarded from the left in the past. This interesting tidbit links the modern world to the ancient world and highlights why so many maritime influences have made their way into air travel.
Next time you fly, you might notice how you board planes from the left. This will always be the case, no matter where you fly. It seems unremarkable at first glance, but it is the result of years of industry standardization and hundreds of years of human maritime tradition.
