Packing a checked bag is one of the easier parts of getting ready for a flight, even when you can't decide which sweaters to bring or your pet won't stop climbing into the open case. It's still a challenge, but the TSA's rules about what can go in a checked suitcase are far more flexible than they are regarding carry-ons. You're only required to pack a few things, like vaping devices and some lithium batteries, in your carry-on bag. You can check most of the things you want to travel with.
Liquids, Gels, Aerosols and Creamy Products
The TSA limits the quantities of certain substances that passengers can pack in carry-on baggage. Liquids, gels and aerosols must be placed in containers no larger than 3.4 ounces, with all containers fitting into a single 1-quart plastic bag. Those limits don't apply to checked bags, so pack full-size containers of shampoo, lotion, toothpaste and other restricted items in this bag. (The only exceptions are breast milk, juice and formula for feeding a baby and medically necessary liquids, gels and aerosols, which may be packed in carry-ons in quantities exceeding 3.4 ounces.)
Something many travelers don't realize is that creamy or spreadable substances like sauces, dips, soups, peanut butter and jam are also subject to the TSA limits. If you're traveling with souvenirs like bottles of wine or jars of sauces, they belong in your checked bag. Gel candles, unfrozen ice packs and other non-solid substances should also be packed in a checked suitcase.
Sports and Camping Equipment
Planning an active vacation? Some of your equipment belongs in checked baggage. Golf cleats, balls and tees may be placed in carry-on bags, but clubs must be checked. Ski boots are allowed in carry-ons, while ski poles and skis must be checked. That should be easy to remember; after all, clubs and poles are too large to fit in an overhead compartment. But it's not just size that's a factor. Anything that could potentially be used as a weapon is generally banned from the plane cabin. Pack tent spikes, fishing hooks, tools longer than 7 inches, Swiss army knives and other potentially hazardous items in checked bags.
Civilians may not pack weapons of any kind in carry-on bags. If it's an item that the TSA and your airline allows travelers to carry, it must go in your checked bag. That's the case for martial arts weapons, compressed air guns, flare guns and firearms. Even realistic toy weapons should go in checked bags. Check the airline's rules about weapons before packing any.
For a domestic trip, it's unlikely you'll need to show a passport at any point or purchase travel insurance. But if you do travel with any special identification or medical documents, place copies in your checked bag in case the originals – which should be in your carry-on – get lost. The rest of your checked items should be things that you won't need to access on the day of the flight and that are replaceable. It's rare for travelers to find that items have been stolen from their checked bags, but it does happen occasionally. Place electronics, valuable jewelry and a change of clothes in a carry-on bag, and pack the rest of your clothes and toiletries in the checked bag.