(I am not sure of where you are travelling to or how long your flight time is for the trip you are interested in taking....)
But, travelling with a six month old is probably going to be a lot easier on you than travelling with a two year old. Once they can walk around all they want to do is the 'circuit'! I also noticed that you mentioned 'he' - a two year old BOY just hates to sit still for any longer than say..... 30 seconds.
If you are going to travel with your beautiful boy when he is a toddler, a trick to making it easier (for both you and your bub - and every pax seated five rows either way) is to bring an extra piece of hand luggage packed full of little toys/blocks/books that will take his mind off the constant desire to climb over the seatback of the person in front of you!
I have done so many flights with my son (who is far more demanding at this age than his sister ever was) it has been a huge eye opener! Every trip is different. I have now learnt not to have any expectations and to just deal with each trip as it comes. I also dont expect to "sit back relax and enjoy the flight!" If I did that I think the poor crew and pax travelling with me would not be impressed!
Good luck! Enjoy that holiday