Getting on a plane is, for many passengers, an automatic ritual. Queue, ticket in hand, narrow corridor and the feeling that the process is the same anywhere in the world. What is rarely questioned is why boarding almost always happens on the same side of the aircraft, regardless of the country, airline or type of flight. The answer has historical roots and also explains the way modern airports were designed.
Those who travel frequently have noticed that boarding and disembarking almost always occur on the left side of the plane. This is neither a coincidence nor a preference of the airlines.
It is a consolidated practice for decades and continues to be followed for reasons of safety, efficiency and standardization of ground operations.
An inheritance from the sea
The explanation begins long before commercial aviation gained scale. According to aviation history experts, many of the rules and concepts used in airplanes were inherited from maritime navigation. Terms such as cabin, cockpit, bulkhead or knots have direct origins in naval vocabulary, and the same happened with boarding procedures.
According to Michael Oakley, editor of , a specialized aviation magazine, ships traditionally dock with their left side, known as port, facing the pier. This convention facilitated maneuvers and the organization of work in ports.
When aviation began to develop at the beginning of the 20th century, this logic was simply transposed to aircraft.
The decision to maintain boarding on the left side ended up becoming a standard. As planes increased in size and the number of passengers grew, standardizing procedures proved essential to avoid confusion and delays.
Attempts to change sides failed
There have, however, been experiments to contradict this rule. In the 1930s, United Airlines attempted to implement right-side boarding on aircraft. The idea was to test new logistics solutions at a time when commercial aviation was still defining many of its standards.
The experiment was eventually abandoned. With the increase in air traffic and the need for faster and safer operations, it became clear that changing the departure side created more problems than benefits.
The industry returned to the traditional model, which was already rooted in the procedures and training of ground teams.
The role of pilots and airports
Another decisive factor is the pilot’s position. Matthew Burchette of the Museum of Flight in Washington explains that pilots traditionally sit on the left side of the cockpit. This position makes it easier to assess distances when parking near the terminal.
As airports became more complex and telescopic bridges, known as jetways, emerged, standardization became even more important.
Building infrastructures designed for a single side simplified operations, reduced risks and allowed different teams to work simultaneously without interference.
While passengers enter and exit on the left side, the right side of the plane is used for other essential tasks such as loading baggage, filling catering and, in many cases, refueling. This physical separation reduces the risk of accidents and speeds up layover times.
A rule that is here to stay
Today, the practice of always boarding on the same side is seen as a logical solution in a highly regulated system.
Uniformity allows pilots, flight attendants, ground technicians and airport operators to work with greater predictability.
For the passenger, the detail goes unnoticed. But behind this seemingly banal routine is a combination of historical tradition, technical decisions and operational needs that have helped shape modern aviation. That’s why, the next time you get on a plane, you’ll do it from exactly the same side as always.
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