On easyJet, passenger age categories are strictly defined for ticketing and safety purposes. An infant is any baby aged between 14 days and 2 years (up to the day before their second birthday). Infants usually travel on an adult's lap for a fixed fee. A child is officially defined as anyone between the ages of 2 and 15 years old. Once a passenger reaches their 16th birthday, they are classified as an adult and are permitted to travel unaccompanied. It is important to note that children aged 15 and under cannot fly alone and must be accompanied by an adult who is at least 16 years old. If a child turns two during their trip, they are legally required to have their own purchased seat for the return flight at the full adult fare, as they can no longer travel as a lap infant once they reach that age milestone.