I wear silk long underwear under my light weight pants and tops. I often get cold on planes, but take it off as soon as we hit the warm weather airport.
We usually stuff our jackets in the outside pocket of our suitcases when we check in our bags at our home airport.
I take sandals, a bathing suit, a clean shirt and some toiletries in my carry on. If my luggage doesn't get to my cabin before dinner, I'm a lot happier if I've been at the pool and can freshen up before dinner.