Everyone has some essentials that they take with them on on holiday whether its in your hand luggage or a must item in your toiletries bag. These are mine.
I shall start with the obvious. Passport. Can not go anywhere abroad without it. I also have this rather lovely leather wallet which was a present many years ago. It has separate areas for your passport, boarding pass, zip pocket for cash and card pockets. It is handy to just carry that around in your hand luggage so when you need to flash your ID, and these days you have to do it a few times before you get through security, you have everything in one place.
My other essentials are things that I need for the flight and basic make up items. Firstly Bach Rescue Remedy. I used to use this a lot in my days of panic attacks but stopped carrying it with me when I got them under control. When I flew last month it was the first time in five years and I was worried I would suffer an attack. I used a few drops of this before I left home and just before taking off. Whether or not it worked I could not tell you, I wonder if its more of a psychological thing, but I flew with no problems so I will take it next time just in case. I did not actually use my ipod during the flight as I was with a friend, but if flying alone it can be useful to just zone out and listen to some therapeutic music, or in my case a holiday play list. And of course a bottle of water is a must. If you fly with low cost airlines nothing is free so after you get through security buy some from a shop before you board, it will save you a lot of money.