just back to vancouver with my son (13 months) 2 months ago, my son is ok wor (this is my son 2nd time on flight, first time we went to japan when he is 10 months), just cry a bit when he want to sleep, and try to request a empty seat beside (if you can) usually the flight attendance will try to give u one if the flight is not full. i bring alot of toys and biscuits because my son loves to eat biscuits also is good to let him eating and drinking during the landing and take off, so they're hear won't hurt much. don't worry too much and enjoy your trip la....
If your son likes to eat then try to bring some more biscuits/snacks for him. Remember to bring new toys also. I've also brought a portable DVD player and let my baby watch the DVD she likes.