I'd like to bring my 5 year old on a work trip I have coming up, but I'm not sure how to ticket him. I'll need to book my own flight through Concur, and our company doesn't allow you to book other personal tickets and then reimburse the company so I'll need to purchase a separate ticket for him.

When I try to purchase a ticket for him online I get a message saying that you can't purchase an unaccompanied minor ticket online. He won't be unaccompanied, since I'll be flying with him. Do I need to book my ticket and then call Delta to add him to my reservation? If I do this would he be on a separate reservation or could he still take advantage of elite benefits (i.e. economy comfort seating, priority boarding, etc.) with me?