In order for your toiletries to be allowed through airport security, you must use a single, clear, quart-sized, zip-top plastic bag. With the exception of the items listed below, the bottles within the 3-1-1-compliant bag may not be larger than 3.4 ounces. To elaborate, 3.4 ounces refers to the size of the container and not the amount of product within said container.
However, the Transportation Security Administration (TSA) will make an exception to the 3.4-ounce rule for reasonable amounts of the following liquids, gels, and jellies:
- Baby formula, food, and juice when traveling with a small child
- Breast milk regardless of whether a child is part of the traveling party
- All prescription and over-the-counter liquids, gels, and aerosols, including saline solution, petroleum jelly, and eye drops that are used for medical conditions
- Augmenting bras or inserts containing gels or liquids
- Frozen items as long as they are thoroughly hard. They may not be partially melted, slushy, or have liquid at the bottom of the container.
- Food-warming ration heaters which often contain liquids and gels
The above-listed items may not be placed in baggies, and must be declared at the security checkpoint.
Medication bottles need not be labeled, and even pill-filled daily dosage containers are allowed. But as with any carry-on item, they may be screened.
Additional permissible items:
- Common gas lighters (no need to place in 3-1-1-compliant bag; torch lighters are prohibited; not allowed in checked bags)
- A single book of non-striking matches (prohibited from checked bags)
- Laptops, DVD players, cassette-playing video cameras, full-size video game consoles, medical equipment - remove all from carry-on bag for individual screening
- Securely-wrapped tools such as screwdrivers, wrenches, and pliers, not exceeding seven inches in length
- Securely-wrapped scissors not exceeding four inches in length
- Plastic or round-bladed butter knives
- Toy weapons as long as they are not too realistic
- Knitting and crochet needles
- Nail files and clippers
- Strollers, baby carriers, and car seats
- Mobility-related equipment such as scooters, crutches, canes, walkers, and service animals
- All diabetic-related items including needles and insulin
- Supplemental-oxygen equipment
- Non-flammable aerosol, gel, or liquid paint not in excess of 3.4 ounces
All of the above information was taken straight from the TSA site though, as many air travelers know, consistent policy implementation has been a constant issue ever since the 3-1-1 rules were handed down in 2006. At times, it would seem that the mood of the TSA screener matters more in what is passed through one airport but confiscated in another. In the end, learn the 3-1-1 rules, but be aware that all items are subject to screening and may even be confiscated if deemed unsafe--including liquid duty-free purchases.