How much is the additional fee for Unaccompanied minors by Delta? Minors between the ages of 5 and 18 years are allowed to travel alone on a Delta flight. However, for children between the age of 5 to 14, it is mandatory to pay the Delta Unaccompanied Minor Fee for the additional services the airlines provide to them. Under this program, the minor travelers are given various facilities like pre-boarding, extra attention and assistance, supervision, snacks, and so forth. Children between 15 to 18 years can take this facility but it’s not compulsory for them if they are traveling alone.