Before my daughter was born, her father and I had a long list of things we wanted to continue once we became parents. Travel topped the list, and when she was just eleven weeks old, we braved our first three-hour flight from Houston to Boston. Since that successful trip, she has been on ten more flights, and she isn't even a year old! We learned a few useful things along the way, and I'm excited to share them with you. My overall advice is travel early and often with babies! Paradoxically, the younger they are, the easier travel companions they can be.
Some airlines allow you to add lap children online, but some require a phone call before check-in. They'll ask the baby's full name and birth date, and you'll need to go to the customer service desk at the airport to get the baby's boarding card.
Most airlines won't ask for a copy of the baby's birth certificate (unless the baby looks suspiciously older than the age limit for lap babies) but Southwest Airlines does require it. We've also traveled with a foster baby and came prepared with a letter of permission for her to travel, but it was never necessary.
Get a carseat bag
One of the best pieces of advice we were given before traveling was to get a carseat bag if you're going to check or gate check your carseat. Sure enough, our carseat bag is all marked up, which is much better than having the actual carseat all marked up.
Stop by your gate
We always stop at the gate before our flight to ask if the flight is full. If the flight isn't full, chances are the flight attendants will allow you to bring your carseat on the flight and use an extra seat for the baby to sleep in the carseat. If you're traveling on your own, this is particularly useful so you can put the baby down safely when you need extra hands.
Don't pre-fill bottles with water
Our daughter was bottle fed, and for the first few flights I would pack water in her bottles and have them specially checked when we went through security (this is simple - just inform a TSA agent that you have water or breastmilk for a baby, and they'll take it away for a quick check). But I always ended up with leaking bottles in the middle of our flight. It must have been sleep deprivation, but I had forgotten that water expands in altitude and would leak all over our diaper bag. Instead, you can buy bottled water or ask flight attendants to fill your bottles as you need them.
Wrap if your baby will tolerate it
When our baby was tiny, I kept her in a fabric wrap (like a Solly or Moby) for getting on and off the plane, and to sleep on the plane. Now that she's bigger, I move her from her carseat/stroller to an Ergo to get onto the plane. It gives me extra hands to deal with bags and getting situated, and it's perfect for naps in the middle of the flight. Keep in mind most flight attendants will ask you to remove the baby from the wrap or carrier for take-off and landing.
Feed or pacify at take off and landing
We try to time bottles for take off, but we've often jumped the gun and been left with an empty bottle while we're still taxiing. In this case, we stick a pacifier in her mouth and have never had a problem with crying from sore ears. If your baby doesn't take a pacifier, this obviously will not work, and you'd want to wait until you're wheels up before starting to feed your baby a bottle!
Routines for rest
If your baby is old enough, work on sleep routines in the weeks before you travel to prepare baby for sleeping in new places. Our daughter now knows that when the pacifier and the lovey come out, it's sleep time no matter where she is. This has been especially helpful for a summer spread between three states and countless different sleeping arrangements!