How I miss having a child I could nurse while flying. It was such a nice comfort, distraction and sleep aid. I'll be honest, there were moments that I had no qualms with using my breasts as a pacify-er to help us out...flying was on of those!
I usually get cold on flights, so I wore a nursing tank, a long sleeved shirt and a cardigan. It made breastfeeding very comfortable and private. My daughter never enjoyed nursing under a blanket or cover, so I just wore clothes that helped make the experience more convenient.
When my daughter was five months old, I never left the ground without a baby carrier (I used an ergo). She took lovely, long naps while curled up in her carrier and I had both hands to eat, read, play cards, etc. We never bothered with extra seats, but last time I flew, got one of the fifty dollar up grades for more leg room. Worth every dollar.
I suggest putting a few of his favorite objects/toys away now, so that they have been missed and hold his attention on the plane. Bring one out, every so often so that they are still fresh.
More than that, you will need rest the night before, liquids (breastfeeding and flying are dehydrating), mama snacks, a good and easy read, mama socks, a good pillow, etc. Get up with him and walk the isles every so often, so that your body doesn't tighten up and so that he gets stimulation and will sit happily in your lap after. If you are happy, he will be happy. Try to talk to your State side friends/family and see if they will take him when you land, so that you can recharge (sleep, stretch, shower) after a long flight. Having a guaranteed break to look forward to always helps me!
I've always found it helpful to bring a blanket for the airport floor. Using airports as a place to let them get their energy out is really helpful. Let him have some time on the ground, encourage him to look around and get stimulated and then, while you're on the plane, he will want to sleep.
When my daughter was very small, it didn't matter when we flew because she slept or was comfortable being held all the time. Later on, I booked red eye flights. She would sleep, I would rest and our fellow passengers were happy.
Good luck and happy travels...you'll be fine!