"If you wouldn't want to spend the flight next to the screaming brat why do you think the parents would?"
Here is a true story. On a trip to visit with family, a relative of mine was on a plane when she was approached by a man, his son, and his young daughter. He walked up to the row my relative was seated in, sat the girl next to her(the flight was not booked), and told that girl that my relative would take care of her. This is not a joke. Thankfully, my relative LOVES children, and in fact, took care of the child, but only because she was not about to ignore the girl. The father did not want to have to look after his girl. He graciously thanked my relative(how considerate).
My relative said that the family were on their way to some sporting event that the boy was participating in(which explains why he and dad sat next to each other talking shop).
That strikes me as a tragedy waiting to happen. Thank God for your relative.