Let’s start with the basics, because the 3-1-1 rule sounds like a code for a secret society. It means: 3.4 ounces (or 100 milliliters) per container, 1 quart-sized bag, and 1 bag per passenger. Why 3.4 ounces? Because somebody in a lab coat decided that’s the exact amount of liquid required to make your carry-on explode into a comedy of errors—but not actually explode.
I must warn you: that quart-sized bag is a liar. It looks big enough for a water bottle and a sandwich, but try fitting a travel-sized toothpaste, a squirt of hand sanitizer, and a tiny bottle of hot sauce from that taco stand you loved. Suddenly, you are performing extreme Tetris while a line of grumpy travelers sighs louder than a dying whale.
Here is a surprising fact: the 3-1-1 rule was born after a 2006 terror plot involving liquid explosives. But today, the biggest threat is that you might smell like a compost bin after a 12-hour flight because you left your deodorant in checked baggage. The irony is thick enough to spread on toast.
