There is a lot of things we have to remember in out hand luggage. The last time we flew to Barbados we ended up doubling our hand luggage after security with all the bits we ended up buying. "Calpol, check, nappies, check, wipes, toys, blanket, dummy etc... The list seems never ending.
To make nappy changes easy for me, I pack a little nappy change kit which contains a nappy, nappy insert and wipes.