Commercial air travel security rules are at odds with your personal goals to secure your person and property. The TSA officers can’t be trusted to respect your valuables. Expensive contents go missing from baggage to parts unknown.
How can you protect your property?
Theft from zippered bags is very easy, and can be done with no trace:
To prevent this breach, you need to switch to hard sided luggage. If you are not prepared to do that, then tie the zipper pull to a handle with a zip tie, and put a mark on that zip tie with a sharpie. To reseal the bag, that zip tie must be cut. You will know the bag has been opened as soon as you claim it at baggage pickup. This is important because once you leave the airport with your bag, the airline may argue that the loss could have happened later.
There are also some products for sale that may help:
But the TSA may still open your luggage as part of their security routine. For valuable jewelry or money, you can take advantage of the security rules for shipping guns. While the TSA must have access to all bags, the exception is shipped firearms. Firearms must be declared, and locked in a hard case with a lock for which only you have the key. If TSA wants to look inside, they must find you, and get the key. They then have to return the key to you when they are done. And all this extra security can be yours without a real gun.
A starter pistol qualifies for all the extra security without requiring all the licensing hassles that surround owning a regular firearm. You just have to follow the rules of the airline and the TSA.
If after all this, the TSA does steal something. File a claim here.