I too fly quite a bit, especially for business and often long international flights.
The advice here is spot on, take something to read or listen to, don't eat too much to avoid the restroom, don't hassle the staff 'cause whatever it is it's not their fault. You can take your own headphones in case they show a movie, or American will sell you a set for $2 you can keep.
At check in, or when switching planes, feel free to ask for directions to your gate.
Arrive at the terminal at LEAST one hour before the flight (this means the terminal, not the parking lot).
More tips on going through security: You'll likely have to take off shoes. Even tennis shoes have a metal shank that'll set if the detectors. If you have shoes that slip on (no laces) wear them at least for the flight. Get all the metal and accessories off of you person and into your carry on bag: wallet, watch, belt if the buckle is big. Keep your I.D. and boarding pass in your hands at security, don't put 'em though the x-ray machine. Laptop, if you're taking one, will have to come out of the bag.
Baggage: for carry on you are allowed one roller-type bag (or a duffel bag of similar size) and a personal item which means brief case or back pack, etc. As stated, carry on your bags if you can travel this light to save a bunch of time when you arrive. If you need larger bags and have to check them, take a carry one with basic toiletries, medication and socks/undies in case your checked baggage is delayed.
They don't allow lighters through security, so leave your Zippo at home. No pocket knives either.
If your flight is delayed to DFW, don't worry about it too much as they will re-book you on the next connecting flight. Plus, DFW is an American hub so there are lots of planes coming and going.
Oh yeah! Enjoy the time with you dad.