Delta said the children were connecting through Minneapolis-St. Paul International Airport on Tuesday when they were put on the wrong connecting flights because of a "paperwork swap."
Delta spokesman Paul Skrbec on Wednesday said a boy ended up in Cleveland instead of Boston while a girl was sent to Boston instead of Cleveland. He would not release information about the children, citing passenger privacy.
WHDH-TV in Boston identified one of the children as 9-year-old Kieren Kershaw, who was flying alone from Spokane, Wash., to Boston to visit his grandparents when his paperwork was switched with the girl's paperwork during the Minneapolis layover. The girl also was traveling alone.
"It was just weird. I was like, 'I'm supposed to be at Boston, not Cleveland.' It was just weird," Kieren told the station after eventually landing in Boston.
Kieren said employees apologized to him when he was in Cleveland.
"'Sorry for leaving you here when you're really supposed to be in Boston,'" the boy quoted employees telling him. "It was kind of nice. They gave me some free food and some Dunkin' Donuts."
Kieren's grandfather, Larry Kershaw, criticized Delta.
"We're paying them to check on him and be with him. They just threw him in the plane like anybody else, they didn't even ask his name to match the paperwork," Kershaw told WHDH.
"Not only that, there's another child, a little girl, that came to Boston. We don't even know who she was. So you mean to tell me you mixed up a boy and a girl and the paperwork?" he said.
Larry Kershaw did not return a phone message left at his Massachusetts home.
Skrbec said he didn't have details about how the mix-up happened and said it was under investigation. Delta said the two children were under airline supervision at all times.
"The situation itself is exceedingly rare, and we take it very seriously," Skrbec said. He wasn't able to give any numbers on how frequently such incidents happen.
Delta's policy for children traveling alone requires unaccompanied service for all children ages 5-14 when they are not traveling in the same compartment with an adult at least 18 years old or the child's parent or legal guardian. Under the rules, an unaccompanied child cannot be booked on the last connecting flight of the evening, to prevent the need for an overnight hotel stay. The policy also sets several identification requirements for the child and for the adults dropping off or picking up.
Delta said it has apologized to the families, sent the children to their final destinations at no cost, arranged full refunds for the children's tickets and provided credits to the families for future travel.