Quick reminder: Necessary documents for traveling with a lap child

Even though my family has moved past the lap infant stage, letting my kids fly for free until they turned 2 was my favorite way to save money (and points) on our family trips. I felt confident in this choice, although I understand it might not suit everyone for various reasons.

Since we usually fly with Southwest (hello, Companion Pass!), my son and daughter often had an empty seat next to them during their lap infant days. If you're new to flying with a baby, be sure to check out TPG's flying with a baby checklist and guidelines for planning award travel with an infant or lap child.)

While many frequent flyer parents are aware that the ideal age range for flying as a lap child is from birth until the day before their second birthday, some might not realize that all U.S. airlines — and likely most international ones too — technically require proof of your child's birth date. Although many airlines might not request this documentation on a given trip, being prepared is essential. Lacking the correct documentation could lead to needing to buy a seat for your infant, and last-minute ticket prices can be quite steep (if there's even availability on your flight).

Keep in mind that for international travel, your infant will need their own passport, whether they're flying as a lap infant or in a purchased seat.

Required documentation for lap infants

To verify your child's age with an airline, you can provide one of the following documents:

• Child's passport (how to obtain a U.S. passport for an infant and key details about children's passports)
• Child's birth certificate
• Child's immunization record or other medical documents may also be acceptable for domestic flights

When my kids were in the lap infant age range, I always kept copies of their birth certificates in the front pocket of my and my husband's suitcases. This ensured we could easily present it to the ticket agent. Having a digital copy on your smartphone is also a smart idea.

Will the airline actually require documentation?

In the U.S., chances are about nine out of ten that you won't need to provide proof of age when traveling with a lap infant on most airlines. However, there is one notable exception: Southwest Airlines almost always requests proof — even if your child clearly appears to be under 2. I was even asked by a Southwest agent for verification when my son was just a tiny 10-pound baby. Southwest's policy mandates checking for age verification on lap infants, so ensure you have the necessary document ready.

Some friends or acquaintances might tell you that age verification isn't necessary for your lap child, but that's simply not the case. While children don’t need an ID for TSA, to fly as a lap infant and confirm to the airline that they are under 2, you must be prepared. If you purchased a seat for your child, no ID is needed since you don't have to prove they are under 2.

In summary

Unless you're flying with Southwest Airlines, the likelihood of being asked for identification for your lap infant on a domestic flight is low (especially if they still appear very much like a baby), but it's always better to be safe than sorry. In the world of family travel, over-preparing with documents is always wiser than being under-prepared.

Have you ever traveled with a lap child? How did you handle proving their age?