To the OP, given the set of laws we fly under, it is just not possible to have an EDC setup in the way some folks traditionally think of it. Being prepared is mental, not what weapons you have.
You will develop a toolkit of items you will take on the road with you, though, in case you get stuck somewhere for a while or are involved in an emergency situation while on a layover. Flashlights, small OTC-medical stuff, cash, etc. There is lots to think about in this department (and a number of good threads all ready in existence talking about it), but none of it will include any kind of weapons.
Your biggest concern, honestly, is having a plan of action for you and your family in the event of a natural disaster or civil unrest. If a catastrophe happens and you are on a flying trip, you will not be able to "jumpseat home" to take care of business. Your family will have to act without you, and you will have to figure out what to do wherever you are located at that time. That plan won't include any weaponry, so you'll have to make do with wits and whatever you have on hand. There may or may not be any assistance from the company to keep you safe, come and get you, etc., so you can't rely on that as your primary plan.
This is no different than talking to your family about how to get out of the house in case of a fire, and where you will rendezvous as a group after you are out. With some experience, you'll develop a better idea of what you're going to want to have, and what you're going to plan on doing.