What is the 3-1-1 liquids rule?

Airport Help each passenger may carry liquids, gels, and aerosols in travel-size containers that are 3.4 ounces or100 milliliters. Each passenger is limited to one quart-size bag of liquids, gels, and aerosols. Common travel items that must comply with the 3-1-1 liquids rule include toothpaste, shampoo, conditioner, mouthwash, and lotion.

Flying with a Dog? Here’s What You Need to Know

So the best information I could find on flying with Pets: https://www.smartertravel.com/flying-with-a-dog/