Involve them in plans for things to do on the journey so they are looking forward to it. If you are travelling by car, look at your route and see if there is anywhere you can stop on the way for a visit or a picnic to make the journey part of the holiday. This also breaks up the journey and gives you a break from driving.
Snacks and drinks
Make sure you have plenty of snacks for your trip. Hungry children (and adults) can be grumpy children (and adults!). Take a variety of snacks, not just sweets, such as crackers, rice cakes, fruit, dried fruit and cereal bars. Make sure you all keep hydrated too. Travelling can be exhausting and dehydrating so having plenty of healthy snacks to keep energy levels up and water to keep hydrated will help.
It is also a good idea to take some baby wipes or antibacterial wipes for cleaning sticky fingers and faces.
Long journeys will mean the need for toilet stops. If you are flying, make sure children go the toilet just before boarding. If you are potty training or your child is recently potty trained it can be a good idea to put them in pull up pants for the flight. That way if they need to go desperately when you can’t go to the toilet, e.g. take-off or landing, then you can avoid accidents. If you are driving, check the route for places you will be able to stop for comfort breaks if needed. This also gives an excuse for everyone to get out of the car, have a break and some fresh air.