I made a travel list which has now gone through several updates as our DD gets older (now 4.5). Here is the first version, from when she was two and just potty training - maybe not entirely relevant, but could be useful. The items in brackets are ones which may be needed, depending on the trip. The second set of things is non-baby stuff that I or the family might need to remember (I usually remember all of DDs stuff and forget half of my own)!
Potty seat, Bowl/cup/fork/spoon, Sippy cup(s), dummies, Bibs, Blankie, Diaper/wipes/cream,Baby Tylenol/Cold/charcoal, [Suntan lotion], bath soap/shampoo/lotion, toothbrush/toothpaste, juice boxes, longlife milk, car seat,
Stroller, toys and books, [videos/dvds], [beach toys, arm bands, float], PJs,
Shoes, Socks, Undies, [Jacket/raincoat/boots/hat/scarf/gloves], [bathing suit/coverup/sun hat], [thermos/insulated bag] hand washing liquid
Camera/charger, Phone/charger, Tums/Pepto, Nurofen, Vitamins, Books, Address list
Airline/hotel cards, Passport photo copies, Make up/hand/face cream, bath salts, Jewelry, Scarves, Sun/reading glasses, [Sunscreen/aftersun], [bathing suit/coverup], [gym stuff]