A Twitter video has gone viral over the last few days, featuring a woman who allegedly 'fat shamed' her seatmate in retaliation to their arms touching during a flight – this, despite the armrest being down.

Amber J Philips, 28, uploaded footage of the woman to her Twitter account after her American Airlines flights from North Carolina to Washington DC ended with police being called.

(Twitter/Amber J Philipsa) Image: Twitter/Amber J Philips

The altercation between the two women began when Philip's seatmate began "aggressively rubbing up against my arm" before asking her to move over (she couldn't, of course, there was simply no room) and "making an active scene" over their arms touching. Since posting the video of the woman online a week ago, it's garnered more than 433,000 views.

Clearly, the issue of personal space on an aircraft is something every plane passenger can relate to, begging the age-old question – who is entitled to the armrests? And what should you do if your seatmate is taking up more than their fair share of space — particularly when it's a larger sized passenger and their feelings are at risk of being hurt?

Armrest etiquette

According to Zarife Hardy, director of the Australian School of Etiquette, good etiquette is simply about making people feel comfortable in your presence.

So when it comes to who gets the armrest, while there are no hard and fast rules whatever people would have you believe, there is a system that's widely accepted as being fairer than others.

"The person seated at the window seat has their own armrest and wall, along with the person seated in the aisle seat – they also have a little more leg room.

"So the person or people seated in the middle generally get the armrests first," Hardy told 9Honey Travel, adding "however let's keep it fair and just wait to see how it casually and politely happens."

But while this approach is deemed fair by many, it's important to get it out of your head that it's a 'rule' (it's not) and adjust your expectations.

Space invaders

Perhaps you're seated next to a larger passenger and they're either willingly or unwillingly encroaching on your seat space. Do you a) start a game of elbow wars and risk the situation escalating? Or b) ask them to move over and potentially humiliate them, as the American Airlines woman did?

According to Hardy, neither of these options are acceptable.

In this most delicate of situations, Hardy says there's a few different paths you can go down but communication is key for all them.

"Talking to your cabin crew privately is a great place to start – do so in the galley, not in front of others.

"Politely ask them if they know of any other available seats that you may be able to move to."

Think you can hold tight until after take-off?

"Wait until you're in the air and see if there are any spare seats that you can move to."

READ: When is it okay to switch plane seats?

If no spare seats are available, then don't underestimate the power of befriending your seat neighbour. After all, it's harder to be angry at someone you're having a friendly chat with, right?

"Communicating with the passenger beside you is also a great solution, especially if there are no other seats available.

"Getting to know someone next to you adds a human element to the situation and [the seat space issue] may be less likely to be a source of frustration or discomfort, it may make the situation a little easier."

(iStock) Image: iStock

Pack your manners

While it's probably easier to think of your space-hogging seatmate as the bad guy, it's important to take the time to remember they're only human and probably not out to ruin your day.

"These days, planes are made to fit many bodies in them and they are often full, seats are not designed for every body shape so just remember people have feelings, be polite and understand that everyone is trying to get from A to B as peacefully, politely and comfortably as possible.

"Switch your manners on."