If it were me,
I'd strike-up a conversation with someone on line
during the screening process in the hope that the
Security Personal would ASSUME that the person
he'd attached himself to was his parent...
when you think about it....from there on out,
he'd be more or less INVISIBLE

The Ticket person would ASSUME he wouldn't be
carrying his own ticket........ get it?

Unless they were really paying attention and
tracking his movements, Security would just keep
passing him through on a series of assumptions,
everyone assuming someone else had seen a ticket.