Listening to the entire video, here’s the story:
The couple have three children (a teenager, a 1 year old, and a two year old,) and they purchased four tickets. The one year old was supposed to be a ‘lap child’ that would share a seat with an adult.
Apparently the one year old was a problem sitting on a lap for six hours, so they wanted another seat to put him in a car seat.
The couple decided to purchase another ticket on an earlier flight for their oldest to fly separately, and use the empty seat for their 1 year old.
But since the older child “Mason” did not check in, Delta sold the seat to another passenger, and demanded that the infant, who was checked in as a lap child, move to a parent’s lap so the standby passenger could be accommodated.
Delta was technically in the right, because since 9/11 you cannot just arbitrarily transfer a ticket to someone else without doing so through the airline.
I suspect that changing the name on the ticket would have involved a rebooking fee and probably have to pay the difference between the original booking and a last minute purchase. (Which is also probably why Delta wanted to sell the seat to the standby passenger. Mo money.)
And the father says (and of course the airline apologist bootlickers immediately dismiss him as a liar), he'd gotten permission from the airline agent at the gate for the switch *before* boarding. Apparently the gate agent failed to communicate this to the onboard staff, who went into Nazi stormtrooper mode as soon as the father dared to challenge their authority.