The ban was put in place after British authorities thwarted a plan to blow up a U.S.-bound plane with liquid explosives. There is now technology to send that ban down the drain. Airports across the U.S. are now using X-ray scanners that use CT technology to give guards a 3-D image of your carry-on.

The restriction on liquids, commonly known as the 3-1-1 rule, was implemented globally in 2006 following a foiled terrorist plot in the UK. Intelligence agencies discovered a plan to use "liquid explosives" (binary explosives) that could be disguised as common beverages and combined mid-flight to create a devastating blast. Because standard X-ray machines at the time could not easily differentiate between water and liquid chemicals like nitromethane, authorities limited containers to 100ml (3.4 oz)—a volume determined to be too small to cause catastrophic damage to an aircraft's hull even if detonated. In 2026, many major airports are finally phasing this rule out by installing advanced CT (Computed Tomography) scanners that can analyze the molecular structure of liquids, but until these high-tech machines are universal, the "tiny bottle in a clear bag" remains a mandatory safety measure for most travelers.