Lap babies are not entitled to the free baggage allowance (carryon or checked). A breast pump does not count toward the carryon limit, but milk may, depending on how it's packed. For example, many pumps are designed with a cooler that's a component of the bag.

On Southwest Airlines, a lap child (an infant under two years old who does not occupy their own seat) is not granted a separate checked baggage allowance. Instead, the standard checked bag allowance is tied to the ticketed passenger. However, Southwest offers a very generous "infant equipment" policy that helps offset this. Each adult traveling with a lap child is permitted to check one stroller and one car seat (or child restraint system) free of charge. These items do not count toward the adult's "two free bags" limit and can be checked at the curb, the ticket counter, or even at the gate. It is important to remember that while the baby doesn't get a suitcase, the adult still enjoys two free checked bags up to 50 lbs each, which usually provides enough space for both the parent's and the infant's essentials. If you find you need more room, any additional bags (beyond the two allotted to the adult) would be subject to standard excess baggage fees, even if they contain only baby items like portable cribs or pack-and-plays.