There are some things about airplanes and travel that we take for granted. We rarely stop to wonder why the pilot is calling everybody “Roger” or what’s going on with meal service up in the cockpit. And today, in not-so-arbitrary-after-all facts about airplanes: why we always board from the left-hand side.
Even on British airlines where — if you think about vehicular driving patterns — boarding from the right side would make sense, passengers still board on the left.
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Of course, there are always exceptions to the rule (small two-seater planes, for example) but for those who fly commercial, the reasoning behind the one-sided boarding is twofold.
“Early airports were set up so that aircraft could taxi in front of the terminal and stop to discharge passengers,” a former U.S. Air Force pilot explained on Quora. “It was useful for the pilot to be able to judge wing clearance from the terminal building and to put the aircraft door in front of the terminal doors.”
Keeping passengers on the left-hand side also keeps them out of the way of grounds crew on the right-hand side who are fueling the plane.
Another explanation comes from the seas. Most people know that port and starboard refer to the left and right sides of a ship. But the etymology of “starboard” actually goes refers to the placement of the “steerboard,” a part of the boat similar to a rudder.
“The placement of this board required that the port side was the one you would embark and disembark from, so most airplane and jetway designers followed the same convention,” Andrew Stagg, a commercial pilot, also wrote on Quora.