I haven't done the international, but flew a lot with my son when he was really young.
My biggest tip is the Ergo carrier. It lets you go through security without taking him off, and you have your hands free for the diaper bag (if you can go with just the diaper bag as carry on, that is ideal). Plus, with the Ergo, you can just sit, and undo the straps and he is cradled in your lap, you don't even have to undo the waist strap. If he falls asleep, just slip it back on, and you don't have to worry about waking him to get on and off the flight, or you can just do it for support so that you can sleep without worrying about him. Also, roll up all the straps as short as possible, and you can go to the bathroom without having to worry about what to do with him.
My son slept during most flights, I think that the sound was kind of soothing to him, but I would go to Walmart/Lowes and stock up on a big bottle of earplugs and put them in a ziplock. This way, if he isn't too happy, you can try to help your neighbors a bit - they will appreciate it. A hooter hider is also great, because if he snoozes while feeding, you can just keep him under there to avoid light in his eyes and there is still some air circulating. A bella band or Blush topless shirt helps keep you modest too, if that is a concern.
Last thing is to know that the magazines are "complementary". My son loved reading/ripping those and it kept him entertained while he was awake. Good luck!