I wouldn't call traveling with kids relaxing, but it is fun, kinda like parenthood. With four daughters and an international business I'm on the go quite a bit and always have at least one of them with me. Here is my number one piece of advice, which all other pieces kind of revolve around, care less! Yep, lower that bar, further, further, yeah right there. When I stopped caring what other people thought when I took my girls places (and in general) everything was much more enjoyable.
Know that people will be annoyed when your baby is crying on the flight, but try and remember that every sensible person realizes you don't want to be traveling with a crying kid either. Try and sooth your baby and don't worry about the grumpy person next to you.
When your on a trip pack light. This way, by the time kids are a few years old they can carry their own backpack. Don't worry about having a bunch of cute picture perfect outfits. They are kids. The most important thing is the experience of it all, not what clothes they are wearing.
Don't stress about time. There are very few things in life you actually have to be on time for, for example, a flight. Although, I have to admit I've missed multiple planes and guess what? There's always another one. If you're worried about rushing to places with your kids, you'll miss out on the enjoyment of lingering moments and unexpected adventures. I like to keep plans very loose. Give yourself the freedom to be where you are and get to where you're going whenever you happen to.
On a practical note, I like to take a red-eye flights. My kids almost always sleep the whole flight. Its less stress to try and occupy them, and you can get sleep too.
Pay extra for a direct flight. I'm always looking for a good deal and I don't mind layovers when its just me, but when I have all my girls and especially if its an international flight, I really don't want to drag them through check ins and customs multiple times. Believe me, you'll have wished you paid the extra $100 per ticket for the direct flight.
Snacks, snacks and more snacks. I always have a bag full of food because being hungry is the number one reason my kids will loose their *hit!
If you're flying with a baby, use a baby carrier or sling ( I always carry my babies in a sling until they are about 2 or 3). Now you have two free arms to grab your bags or other kids.
Do not, I repeat, do not take a bulky stroller or car seat with you! They are so cumbersum and make travel difficult, especially if you're going without another adult. You can get car seats from rental car companies for a very small fee. If you really think you need a stroller, grab a cheap umbrella stroller from a local store upon arrival and then give it to someone when you leave.
Whatever you think you need, you probably will only use a fraction of it. So, make it easier on yourself and I repeat pack light!
Hey, I'm not an expert with this stuff (isn't that what everyone says), I'm just one traveling mom giving her two cents to others.