Yes, you are absolutely allowed to bring your own snacks through airport security, provided they are in solid form. Items like sandwiches, crackers, nuts, fruit, chocolate, and protein bars are perfectly acceptable and can save you a significant amount of money compared to airport prices. The "hard line" for security is the 3-1-1 liquids rule: any food that is considered a "liquid, gel, or aerosol" must be in a container of 3.4 ounces (100ml) or less. This includes snacks like yogurt, peanut butter, hummus, pudding, or even some soft cheeses like brie. If you have a large jar of peanut butter, it will likely be confiscated. However, if you purchase these items after you have passed through the security checkpoint, you can bring them onto the plane regardless of their size. It is also important to remember that if you are traveling internationally, you must usually consume or discard any fresh fruits, vegetables, or meat products before you land in your destination country due to strict agricultural and customs laws. To speed up your trip through the X-ray, it is a good idea to pack your snacks in a clear bag and place them in a bin if requested by the TSA officer.