The most effective way to secure your luggage against theft when flying on commerical airlines is to travel with a firearm. When flying with a firearm you are required to store it in a hard case with a lock to which ONLY YOU have a key. The TSA is prevented from both opening your luggage once sealed or marking it in any way to indicate contents. Watch the video for more detailed information. NOTE: If you are uncomfortable with firearms, the firearm you travel with does not have to be deadly (i.e. it can be a flare gun).