All About the TSA Carry-On Rules

If you're traveling with the family, you probably want to be in and out of those airports as quickly and smoothly as possible—meaning if you can skip the baggage check, you will.

But to succeed in carry-on travel, you first have to master the Transportation Security Administration's (TSA) rules for carry-on baggage. As a rule of thumb, firearms and explosive or flammable items are prohibited, as are most sharp objects. But beyond that, the rules can get a little confusing.

This one's probably the most important to know: Liquids, aerosols, gels, creams and pastes are permitted in carry-on bags in very limited quantities. They must be in 3.4 ounces or smaller-sized containers, and the containers must fit in one quart-sized resealable bag. The TSA often refers to this as the "3-1-1 rule," 3.4-ounce containers in one 1-quart bag.

The only exceptions are for medications and some foods for infants and children.

The TSA gives special carry-on treatment for water, baby formula, breast milk and juice for infants (children who must be physically carried by an adult through the screening process) and toddlers (children who receive adult assistance to walk through the screening process).

If you're bringing liquid sustenance for your infant or toddler in a carry-on bag, it's allowed in "reasonable quantities" through the TSA security checkpoint. Notify the TSA officer at the beginning of the screening process that you're carrying formula, breast milk or juice, and remove the items from your bag to be screened separately.

Ice packs, freezer packs and frozen gel packs used to cool these foods are also allowed in carry-on luggage. If they are partly frozen or slushy, you'll need to remove them from your bag to be screened separately, as well. You can also bring liquid-filled teethers as well as canned, jarred or processed baby food in a carry-on, though they might also be subject to separate screening.

The TSA provides an extensive list of foods that are permitted in carry-on bags, but it boils down to this: Foods that are considered liquids or pastes are subject to the liquids rule, except for the foods described above.

If you're bringing ice packs to cool your food, they should be completely frozen when they go through the screening process. (Oh—and if you're transporting a live lobster, you might want to check your airline's policies, though the TSA says it's fine as long as it's in a clear, plastic, spill-proof container.)

Certain toiletries fall under that "sharp objects" category you generally want to avoid when packing your carry-on luggage, so vet your makeup bag carefully. Disposable razors are OK, as are tweezers and sheathed scissors with blades smaller than 4 inches. Pretty much any other sharp item is prohibited.

Liquid deodorant is, as you might have guessed, subject to the liquids rule. But if you're a fan of solid deodorant, carry on as much of it as you'd like.

Most toys are OK for carry-on bags by the TSA's standards, with the exception of:

• Foam toy swords
  
• Realistic replicas of explosives
• Realistic replicas of firearms
• Water guns
• Sports equipment that can be used as a bludgeon (bats and golf clubs included—tennis rackets are OK)

If you have any items you're unsure about, you can contact the TSA's AskTSA team via Facebook or Twitter. Send the team a photo of the item in question and ask what the TSA's rules on it are.

Now that you've got a solid idea of what the TSA will and will not permit in a carry-on bag, it's time to worry about the hard part: How to fit everything you need into a bag that's standard carry-on size.

Carry-on sizes vary between airlines, but they usually can't exceed 45 linear inches. For that reason, you often see dimension limits such as 22 inches x 14 inches x 9 inches, which means you need to pack resourcefully to make it through the trip.

Consider using a vacuum storage bag to pack your clothing and other soft items as efficiently as possible. Reusable compression bags can make a big difference as far as saving space goes, leaving room for the non-essential items that might make your trip a lot easier, such as blankets, neck pillows and games.

And remember that you're also allowed an extra bag that can fit below an airplane seat. Make the most of this by bringing along your hardiest tote bag or backpack and filling it with the items you'll need the easiest access to during your flight, such as snacks and books.