I'm now finding it pretty easy to travel with my ds (3). We travel quite a lot so I think I've the packing pretty sorted. And boy is my list shorted than when he was a baby!
I divide my packing list for him into categories to make it easier for me to work out what we need and spot what's missing.
(This is off the top of my head so please do check!)
Here is mine:
CLOTHING
UV tshirt
UV shorts
sunglasses
Hat
4 pairs shorts
2 pairs lightweight long trousers for flight/ evenings in case of mozzies
Sandals (pref crocs or washable ones in case of wee accidents!)
Swim/ beach shoes - I like those neoprene ones with non-slip soles.
PJ bottoms
Tshirts - depends how messy he is but I take about 4 or 5 for a week ss plus 2 long sleeved (air conditioned hotel rooms can be a little chilly at night!)
HEALTH & PERSONAL CARE ETC.
Toothbrush and kiddy toothpaste
Nailclippers
Thermometer
First aid kit (v. small one from boots)
Calpol sachets
Arnica cream
wipes
insect repellent
sun creams
PLAYING
crayons and paper
teddy bear for bed
Fave vehicles
'playtray' (a great idea I picked up from someone else - take a cardboard box's lid, which is white on the inside, draw road/ train track, add stickers or pictures of ds's fave places, even people and bingo he can send his little cars trains around it on his lap without them falling off!)
DVD player or laptop pc if you have one for dvd on the plane (although we often manage without this)
A few other compact fave toys packed into a small kids' rucksack that can be taken on plane and then used when you go to dinner and they get gripey.
Mini magnetic drawing pad
Sticker books
EATING
One non-spill cup for night time and days out
Cereal bars for on the plane and snacks when there (they are v light and don't tend to get squashed)
A few packs of choc buttons/ those small bags of biscuits (for emergencies like very long airport queues)
HTH.