If a child is aged 17 and under, and traveling alone or without a PreCheck eligible parent or guardian, they will need to apply for PreCheck for themselves. However, children aged 12 and under traveling with an eligible adult, can join their parent or guardian in the PreCheck lane. Children aged 13 to 17 may also go through the PreCheck line with their eligible parent or guardian, but they may be randomly excluded, which would mean they would need to go through the standard security screening process.