Went to Canada with my dd at 12 months. was great, no problems, based on the following tips!
book night flights where possible
buy those straps that attach toys to pushchairs/car seats and use them to attach a few toys to the plane seat/the tray in front of you and the buggy at all other times, saves bending down all the time when they fling them on the floor and/or losing things
medised....can't stress this one enough!! but do put it in a small bottle as per the airline rules on taking meds/liquids, the bottle must not exceeed a 200ml capacity.
ready bottles of milk and disposable bottles (if yr baby is not breast fed)loads of wet wipes and changes of clothes/sleepsuits worked well for us. remember it is actually often hot on planes, i forgot this and took too many layers for our dd. she did get filthy dirty though!
paper disposible bibs, saves carrying around dirty milky cloth ones.
sorry if these points have already been made, i didn't have a chance to read all the posts!
PS BrightonNm.....don't worry about the jetlag, just get a night flight and dose him/her up with medised. the younger they are the easier the jetlag. just get them out in the sunlight when you want them awake...this is really important. use dark/light to get them to sleep or be awake to get their diurnal rythms going!! don't stress, your jetlag is much more likely to be the problem than theirs! also read Tracy Hoggs books on travelling with baby. (not sure if its the baby or the toddler one but lots of helpful tips)
hope this helps!!