In 2026, traveling for 5 hours with a newborn is considered safe by pediatric experts, provided you follow the "two-hour rule." This rule recommends that infants should not be in a car seat for more than two hours at a time, as the semi-upright position can potentially restrict their developing airways or cause "slumping," which impacts breathing. For a five-hour trip, you should plan at least two substantial breaks where the baby is taken out of the seat and placed on a flat surface to stretch and breathe freely. If you are flying, the pressurized cabin is generally safe for full-term healthy newborns, but many doctors suggest waiting until the baby is at least 2 to 4 weeks old to allow their immune system to develop. During takeoff and landing, feeding the baby (breast or bottle) helps equalize ear pressure. Always ensure the infant is secured in an FAA-approved or crash-tested car seat, and never leave them to sleep in the seat once you've reached your destination, as it is not a substitute for a firm, flat crib.