Frontier Airlines offers unaccompanied minors service to fly alone. Children between 5 and 11 years old can travel solo, and if they are 12 and 17, they can fly solo as per Frontier Minor Policy. Children below 5 years old cannot fly alone. You can visit the Frontier Airlines official website or get more information about Frontier Policy or how you can book a flight solo for your ward through the mentioned link. Feel free to speak to a customer service representative if your children are traveling on Frontier Airlines.