If you're traveling with a 6-month-old baby on United Airlines, add a lap child on united, you can either place them on your lap as a "lap infant" or purchase a separate seat for the child and bring an FAA-approved car seat to keep them safe during the journey. To find out about unaccompanied minor services, call United customer service. Furthermore, tickets are available for purchase on the official website. Inform the airline about the child's airport pickup and drop-off. To make an unaccompanied minor reservation.