WiFi in the is becoming more common now, but when it was first being rolled out, for the most part it wasn't actually kids who were the most annoying.
"HEEEY Guess what! You'll never guess where I am!"
"Look! LOOK! Isn't this just so cool?"
"Yeah we're going on vacation, this is going to be so awesome"
"Blah blah blah blah blah blah"
Repeat throughout the whole flight.