I speak of passenger aircraft that can be found on large airports. The left side is used by passengers (and the crew) to embark/disembark (see the position of jet bridges) and the other side to embark/disembark the rest (e.g. food).

Why do we always use the left side for passengers? What prevents an airport from deciding to use the other side?

If this is an historical decision (e.g. one day in the past an aircraft builder decided passenger should use the left side, then majors airports were built accordingly and thus new aircraft were built accordingly and thus new airports were built accordingly), is it possible and reasonnable to build a jet bridge made to operate on the right side of an aircraft and then use the right side for passengers and the left side for the rest?


4 Answers 4


Why do passenger embark on the left side of an aircraft?

Because the cavewoman who invented the log-canoe was right-handed?

Note: I arrived at this answer by looking at a kind of etymology of the terms starboard & port but that's incidental. The answer to this question happened to be contained in an answer to a rather different question. Some groups of aviators may have dropped the archaic terms while still being subject to a continuation of an archaic habit/convention.

People get on the left side of a jet airplane because Vikings (etc) steered their wooden boats with a steering board (hence starboard?) held in their dominant right-hand.

Since it was inconvenient to have your steering apparatus wedged against a quayside (or earthen bank) they docked at the port along their left side and therefore loaded and unloaded on the left.

Farhan's comment leads you to this answer in English.se which I reproduce here for convenience

Excerpt from trivia on the Navy website:

Port and starboard Port and starboard are shipboard terms for left and right, respectively. Confusing those two could cause a ship wreck. In Old England, the starboard was the steering paddle or rudder, and ships were always steered from the right side on the back of the vessel. Larboard referred to the left side, the side on which the ship was loaded. So how did larboard become port? Shouted over the noise of the wind and the waves, larboard and starboard sounded too much alike. The word port means the opening in the "left" side of the ship from which cargo was unloaded. Sailors eventually started using the term to refer to that side of the ship. Use of the term "port" was officially adopted by the U.S. Navy by General Order, 18 February 1846.

So it's a historical convention, many arbitrary choices are of this sort. Pioneers of a new form of transport adopt the terms (port, startboard) and habits of more ancient forms of transport.

Ironically, since aircraft became able to carry substantial non-human cargo, the cargo entry has moved to the other side to reduce the chances of crushing the human cargo with the non-human cargo. Presumably also because having lots of large holes all in one side may be structurally disadvantageous.

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    $\begingroup$ As an ROTC cadet and private pilot, I must say, I have never legitimately used the terms port and starboard. $\endgroup$
    – Keegan
    Commented Oct 14, 2014 at 0:42
  • $\begingroup$ @KeeganMcCarthy: The terms “starboard” and “port” were and may still be used in RAF and US Navy, but not so much elsewhere and certainly not in civil aviation. $\endgroup$
    – Jan Hudec
    Commented Oct 14, 2014 at 6:52
  • $\begingroup$ @JanHudec Isn't there something about the Navy NOT using the terms for their aircraft because once aircraft is carried on ships, it would be confusing? Or is that just a QI fact? $\endgroup$
    – biziclop
    Commented Oct 14, 2014 at 12:11
  • $\begingroup$ @biziclop: I don't know really. I know RAF used it, but don't know whether they still do and I don't know whether Navy applies or applied them to aircraft or only to ships. $\endgroup$
    – Jan Hudec
    Commented Oct 14, 2014 at 13:46
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    $\begingroup$ @aitchnyu That link specifically says that the quoted claim isn't true... funny as it may be. $\endgroup$
    – reirab
    Commented Aug 14, 2015 at 12:27

Early fighters with a cockpit (Supermarine Spitfire, Messerschmitt 109) had cockpits which were hinged on one side. For a right handed pilot (the majority), it was easier to lift the canopy over your head and to the right, hence the hinge was on the right. It's also easier to climb up an aircraft if your stronger arm is toward the fuselage and handholds.

This made the left the obvious choice for disembarking, and since airfields slowly became set up for exiting to the left and fuel to the right, newer designs maintained the door on the left. If your stands are set up for one direction, you may as well order your new plane to fit the same workflow, so even when hoods were modified to slide backward, there was no need to change the door side (most designs were incremental, so the door was already there... Why move what already works?)

This continued as air bridges and similar were introduced, and it would now be pointless to make an aircraft with doors on the other side, as you'd just be increasing your loading/turnaround times.

  • $\begingroup$ The Spitfire and ME109, however, were inter-war designs, and passenger aircraft were available before that. Also, every commercial airliner I've been on does have a door on the right, straight across from the door I've entered on the left. It's used by catering to get food on/off the plane as well as the cleaning crew entrance/exit. Therefore, it's not really "pointless to make an aircraft with doors on the other side". $\endgroup$
    – FreeMan
    Commented Oct 7, 2022 at 17:13

I expect it comes from the fact that aircraft development started in countries that drive on the right side of the road. The pilot sat on the left because, well, that's where drivers sit. The early airliners would park with the "terminal" / shed / tent / hole in the fence on the left side so the pilot could steer without hitting anything (better view out the window), the pilot could climb out his door and open the rear door to unload the mail without walking around to the other side of the plane so that's where the cargo handlers / trucks / horses would wait.

Remove the front door on larger aircraft, replace it with a rear door closer to the ground. You still put it on the left for compatibility with all the other stuff flying. Fast forward to the modern day and we find that we have to pick one side or the other, everything has a left door, some have doors on both sides, so....

I've considered that monsters like the A380 should use jetways on both sides but making a jetway reversible is mechanically very complex. Economics kick in here as the largest planes are not used for short routes where a 30-minute turnaround matters. The cost of dual-side jetways doesn't have a reasonable payoff.

  • $\begingroup$ Just FYI, the A380 is typically loaded with three jetways -two for the lower deck, one for the upper deck. $\endgroup$ Commented Oct 13, 2014 at 13:55
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    $\begingroup$ @BurhanKhalid but all from the left. $\endgroup$
    – casey
    Commented Oct 13, 2014 at 14:09
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    $\begingroup$ My $0.02 worth: This may be right but it seems to be pure speculation. Some supportive historical references would be useful. $\endgroup$ Commented Oct 13, 2014 at 14:34
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    $\begingroup$ I don't buy this. You're saying that it's because planes evolved in countries that drive on the right but parking with the left side of the vehicle at the side of the road" is a property of countries that drive on the left! $\endgroup$ Commented Oct 13, 2014 at 18:50
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    $\begingroup$ @DavidRicherby Cars park on the right so the driver can see approaching traffic when he pulls out. Planes parked with the building on the left so they don't hit it with the wings. In both cases it's operator visibility of the most hazardous obstacle. The curb can take a few tire hits. So can the tire. $\endgroup$
    – paul
    Commented Oct 14, 2014 at 12:20

The earliest air forces in Europe derived from cavalry regiments, flying was expensive and the preserve of the rich - as was the cavalry.

Because a right handed horseman carries his sword on the left, he will mount a horse from it's left side - so he throws his right leg over the mount.

This is why the pilot in command sits in the left seat and enters from the left side of the aeroplane. When passengers started entering through a door the same tradition continued.

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    $\begingroup$ Citation needed. In early planes, the pilot sat in the centre and that probably lasted for long enough for them to forget they used to be in the cavalry. $\endgroup$ Commented Oct 13, 2014 at 18:52
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    $\begingroup$ But they stepped aboard from the left. Some airforces still haven't forgotten they are cavalry, having warrant officers rather than sergeants for example $\endgroup$ Commented Oct 13, 2014 at 18:53

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