Has anyone send their kid on a flight as an unaccompanied minor? What airline did you use?

I never let my kids travel on their own. But I know Singapore Airlines has this special services for children aged between 5 to 18 years old to travel without adult. But you have to notify the airlines before hand. You can read up the procedures to apply for this service from here https://www.singaporeair.com/en_UK/travel-information/travelling-with-children/ For other airlines, you might want to check their website or call them directly.