The carry-on rule
Toothpaste counts as a liquid or gel at security. Each container has to be 3.4 oz (100 ml) or smaller, and all of them go in one quart-size clear bag. TSA notes that the final decision rests with the officer at the checkpoint.
Packing it well
Cap the tube firmly and pack it upright in your liquids bag. Pressure changes in flight can push paste toward the cap, so open it over the sink the first time you use it after landing.
Traveling with kids
Pack each person’s own brush, and let kids carry their own tube in their backpack so bedtime away from home still feels familiar. Keep the routine and the song the same as at home.
