The thing about jet lag is that it's probably worth it. How boring would life be staying in the same time zone? Jet lag means you're traveling to far away places that you see in National Geographic, and showing your children new cultures, new landscapes, new food, and new languages.
Yes, you're going to be a little sleep deprived for a day or two on either end of the trip, but didn't we all sign up for sleep deprivation when we decided to have kids?
I think what parents are most worried about is throwing their finally sleep-trained baby way off their schedule, never sleeping again, and regretting their trip forever. That's just not the case. You're baby will get back to their routine, your baby will sleep through the night again, and you will resume life as normal (but with some cool experiences under your belt). But just like I tell my son as he's screaming for orange slices as I'm actively peeling an orange as fast as my little fingers can, "paciencia, mi amor".
Z waking up after a jet-lagged nap in the middle of the Mekong Delta.
TIPS FOR COPING WITH JET LAG:
Give yourself a cushion. Don't plan anything crazy on your first day or two of your trip. Give your family some time to catch up on some missed z's. The good thing about flying to a new place is that you land in a city - the perfect place to find a comfy bed and spend the days moseying along, eating, drinking, and sightseeing. When planning your trip home, leave a day or two before you have to go back to work.
When the sun is up, soak in that Vitamin D. Hanging out in your room during the day is going to make you lethargic and your family cranky and cooped up. Get outside and get that sunlight. This will help your baby adapt to the new time change and get his circadian rhythm in the right time zone.
Embrace the 2am pancake breakfast. Your baby is going to wake up in the middle of the night while they are adjusting. Chances are, though, that you will be on the same schedule. Go with the flow in this case - it won't last forever. Keep the lights low and the mood mellow. Soak up some midnight snuggles, have a pancake breakfast at 2am, read some books, then go back to sleep.
Screen time is your friend. This one might be controversial, but it was what I had to do out of desperation. Adjusting back from a 12 hour time difference took about 5 days. The hardest part of that was keeping Z awake until a normal(ish) bedtime (6:30pm). Doing this while fighting off extraordinary drowsiness myself was my Everest. Reading to Z was putting me to sleep and it was freezing rain outside, so my second tip of soaking in the sun was not an option. I turned on a PBS cartoon, and it kept the baby boo awake. Yah gotta do what yah gotta do. I can't imagine that 3 hours of screen time in the first year of a baby's life is detrimental.
Don't adjust. If you are traveling for less than a week, you may want to consider not adjusting your baby to the new time zone (depending how long the trip is).
Coming home is harder. Switching back to your home time zone is usually more difficult than adjusting to your destination's time zone, so keep that in mind while planning your trip.
Get active. Exercise is the best medicine to fight off jet lag for adults and children. You want to sleep at an unnatural time when you're usually wide awake? Exhaust your bodies and you'll sleep.