According to United Airlines' unaccompanied minor policy, a 150 USD service fee per way is applied to the cost of each ticket for every second child travelling unattended. Included in this are the extra services offered by the United flight attendants and airport personnel. If you buy flights through, a United Airline Unaccompanied Minor Fee will be added to the cost of your child's ticket. When you pay for your child's ticket through the United customer service number, the airline will take the cost.