It takes several hours on a plane to get to Europe or other overseas destinations. Adults typically can't make this trip without a trip or two to the lavatory for relief, so obviously a baby isn't going to make the trip without soiling itself.
Note of the total number of hours your itinerary covers and then pack one diaper for each hour of the flight, then add one or two in case of delays. You'll also want to pack a changing pad, because you never know where you might need to lay the baby down to change the diaper. There's a good possibility it won't be as clean as you wish.
It is important to carry some plastic bags that will easily seal to dispose of dirty diapers along the way. The people sitting near you on the plane will certainly appreciate this thoughtfulness.
If your baby uses a pacifier, you already know that you'll need to bring one. But you should also pack several more.
Pacifiers keep babies calm on long, boring flights and often help them to sleep. Sucking a pacifier also relieves ear pressure associated altitude changes during flight.
Even without the airplane-related benefits, there is the possibility of loss or simply dropping one on the floor of the plane, where it will get dirty. With extras, you'll never have to worry about finding a place to buy new ones.
Pack a battery-powered light for the trip. Your hotel room may not have adjustable lighting or lamps. Overhead lighting is too bright to turn on in the middle of the night in the event that the baby wakes up and needs your attention or a diaper change. A small battery-powered light is useful to keep by the bed and will give you just enough light to complete the task without disrupting the calm, dark surroundings.
Bring along plenty of baby food or formula, depending on the age and appropriate diet of your baby. You can always get more when you reach your destination, but you will need a certain amount to get through the trip. If you breastfeed, pump enough milk to last through the flight if your airline will allow you to bottle enough milk.
Planes are notorious for becoming too cold in flight. Babies are more sensitive to the cold than adults are and must be kept warm to be comfortable. Be sure to being along a light blanket and a beanie cap to keep your little one warm during the flight.
Babies have accidents on a regular basis. Sometimes bodily functions soil their travel outfit. Make sure you pack a change of clothes in your carry-on bag so you can change them into clean clothes if necessary.
