I flew long haul with my DS at 6, 8, 10, 12 months, sometimes alone. Lots of snacks to kill time! I gift-wrapped some new toys for the flight too but probably needn't have bothered. Like PP I prepared for lots of activities but didn't need them. He was feeding a lot of the time, eating snacks, playing a bit, and sleeping.
We have a Babyzen yo-yo buggy which can go into the cabin as it fits overhead.
I had no nastiness, only kindness from other passengers. The flight attendants really looked after us as well. They made sure I had an empty seat next to me (none of the flights were full) and I was on the bulkhead/bassinet position.
Check with the airline in advance about bassinets for infants and seating arrangements. Also food, some flights we got free Ella's pouches I think.
Will be interested to hear about CARES too as we are about to fly with a 3 year old and 4 month old and we are likely going to get one.