For the plane, take plenty of nappies in case of delays. Feed dd during take off and landing so her ears don't hurt. She'll probably be happy just sitting on your knee but take a couple of small toys.
Buy a cheap second hand buggy, it'll get thrown about by the baggage handlers. You can usually take it to the gate and then hand it over, check on the airline website. Also take a sling if she likes it.
You can buy nappies there, just make sure you know her weight in kg as sizing isn't always the same. We usually just take 2-3 days worth of nappies until we find our feet.
Most airlines will let you take a changing bag on board as baby's hand luggage, plus two baby items in the hold, for example cot, buggy or car seat.
Lots of sun cream. Sudocrem is good as aftersun too.
If you don't want to carry a heavy travel cot, you can buy a koo-di pop up travel cot and sell it on afterwards. They're very lightweight.
Don't forget things like bottles and bottle brush. Makes life so much easier!