This was LJ's third international trip, he came with us to Walt Disney World last May and then to Thailand for a wedding last August. However, we knew it would be the first trip he would be mobile and he was also going to be too big for the bassinet (we affectionately call him the monster and at 12kg and 84cm tall he lives up to that name), so we made the decision that we would purchase a seat for him as opposed to nursing him on our lap the entire way. We are so glad we did this; none of us would have survived the flight if he were on one of our laps with a stranger sitting in the third seat of our row. It definitely wasn't the cheapest option but the 9 hours of sleep we got out of him on the way home made it worth every cent.
When we selected our seats I purposely avoided the bulkhead seats. They would have offered more leg room but the arm rests are fixed and wouldn't allow LJ to lay across the seats with his head on one of our laps, which is how he spent most of the trip.
We also purchased a CARES harness, which allowed LJ to sit in his own seat for take off and landing. This wouldn't work for all 1 year olds, as it is for kids between 10kg and 20kg, but I felt much safer with him in the harness during take off and landing than I did with him in my lap. Delta doesn't provide the lap belts for infants that Qantas do, so this was even more important to me. He didn't love being in the harness all the time, so once the seat belt sign came off we would leave him in the lap belt only or he was being held by one of us. As he gets older and understands more of what is happening he will hopefully get more comfortable with wearing the harness for longer. I imagine we'll continue to use this beyond 2, even though it's not required after that point, to maximize his safety. The harness was super easy to install, especially with early boarding for families, and was nice and small for transporting. It has a strap that goes around the seat back (you have to put the table behind you down to tighten it and then the table closes over it) and two sholder straps that have loops for the lap belt to feed through. You then buckle the lap belt and the chest strap to secure the harness. LJ did slide down a little at times, since there isn't anything between the legs, but it wasn't too much of a drama.
LJ all strapped into his CARES Harness. You can see the red strap that goes around the seat back in the top right and the black straps that hold him in.
I had purchased LJ some volume-controlled headphones for the trip but LJ's still a bit young to sit and watch the shows on the personal entertainment systems. He was happy enough with just the pictures and preferred pressing the power button continuously to watching the shows.