11. Paracord
A strong rope can be used in numerous ways, including tying a door shut or making a trap to protect you from nefarious individuals.
The commercial grade 550 pound nylon cord from Paracord is durable, strong and compact, which makes it a good choice for flying.
Like many of the items on this list, the Paracord might end up in your checked luggage to conserve space.
Although this is not ideal, it is worth paying for a bag and taking the risk of being separated from it in order to keep such an extensive amount of survival gear with you when you fly far away from home.