We've all been on a plane, squashed into the middle seat between two people we don't really know and had to weigh up the 'armrest debate'.
The people on the inside and outside each have at least one, but there remains a grey area for the two in the middle.
No doubt there have been countless arguments when family members have had to sit beside each other, and even some awkward moments with strangers when one person tries to establish dominance by taking both of them.
The long-standing question remains though: who gets to use the middle armrests in a plane?
Well now, ladies and gentlemen, we have a definitive answer.
Boris Millan is a travel writer and has penned a novel The Common Sense of Flying.
He appeared on a travel podcast, Confessions on the Fly, to talk about one of the chapters - specifically, the one on plane etiquette.
He told the two hosts, Laura Salerno and Flight Attendant Jo that it's the middle seat who holds the power!
He explained: "They did a lot of research in the UK for some reason about this - when you sit in the middle seat, you get to have..."
LJ cut in to say: "You get both armrests!"
And Boris agreed, "It's common sense, guys. It's common sense."
There is indeed form for this theory.
Etiquette expert Jodi RR Smith told Reader's Digest that the middle seat was the one to have for the armrests.
He explained: "When sitting three across on a plane, the person in the middle has dominion over both armrests. The person on the aisle has the benefit of being able to move freely and has stretching room into the aisle. The person at the window has the benefit of leaning against the window or being able to see the view, when there is something to see.
"But the person in the middle is not able to easily move or stretch, nor is there anywhere to lean. Therefore, they have control over the armrests."
Benét J Wilson, travel writer for The Points Guy , agreed, saying: "The poor person stuck in the middle seat deserves both armrests. The window person has the fuselage and control of the shade. The aisle person has access and can put their leg out when the flight attendants aren't serving."
