Hi Expectant,
Ask for a bassinet, so that you can put your baby down, although you can't keep the baby in there if there is turbulence.
If you can afford it get your baby his own seat and take your car seat (make sure that it will fit) - we didn't do this, but would give you some more space.
Put him in a baby grow, and just take several more baby grows for changes of clothes. They are about the right temperature for the plane and you don't have to worry about pyjamas or day and night etc.
breast feed at the smallest cry - but in my experience you don't need to do this on take off or landing, even though people will tell you that you do.
play with him on the changing table in the loo if he likes bright lights.
ask the stewardess to keep an eye if he is sleeping in the bassinet and you need to go to the loo. alternatively take lots of towels and lie him on a towel on the loo floor if you are travelling alone and need the loo.
calm him down in the loo if he is screaming his head off
bring a mountain of wipes and alco gel if you are going to spend any amount of time in the loo.
bring a sling.
walk him up and down the plane in the sling until you are both bored out of your minds.
book a night flight so he will sleep for the majority of it
once you arrive keep him awake until his new time zone bed time
let him watch TV