When you get to the airport, go to the SW counter or kiosk and check in. They'll weigh your suitcase and take it or direct you to a place nearby to hand it over to the baggage folks. TSA will x-ray it as it makes it way to the plane, and they may enter it if they want.

SW site says they allow 50 lbs per checked suitcase. Overweight item is $100 for 51-70 lbs. Put a sheet of paper inside with your name and cell in case it gets lost and someone gives a damn about getting it back to you. You can lock it with TSA approved locks that you can buy on Amazon, Walmart, etc. The approved locks allow TSA to enter with a master key but may deter a casual thief. Tie an odd color ribbon on the suitcase handle so you can spot it when it comes out of the baggage carousel at your destination airport.

For carry-on items, TSA says:

quote:
You are allowed to bring a quart-sized bag of liquids, aerosols, gels, creams and pastes in your carry-on bag and through the checkpoint. These are limited to travel-sized containers that are 3.4 ounces (100 milliliters) or less per item. Placing these items in the small bag and separating from your carry-on baggage facilitates the screening process. Pack items that are in containers larger than 3.4 ounces or 100 milliliters in checked baggage.

Read SW policy on max size/number of carry on items.

So have any contact solution, toothpaste, shaving cream, etc. that you want to carry on in a 3.4 oz. or smaller size, and put all those in a single quart zip lock bag. If you have bigger size liquids, pack them in the checked suitcase (also in a zip lock bag to avoid leaking issues)

After you check in at the counter, get a boarding pass, and hand over your checked suitcase, you will proceed to TSA screening with your carry on items. They will have you remove shoes/belt and place them and your carry on bags, pocket contents, etc. in a plastic bin to go through an x-ray/conveyor belt. You will walk in your socks, while holding up your pants, through a separate machine for x-ray/metal detection. You and your items will be reunited on the other side if all goes well.