Several years ago, on a trip from Berlin to Indianapolis, I learned the hard way, that I should never fly without chewy granola bars. Just like the commercial suggests, whenever one of the kids starts saying too much, I pull one out and feed it to them.
When my daughter was three years old, she took a liking to the Italian woman sitting across from us, and fortunately, the woman took a liking to her. Initially, there was a bit of an accent barrier, but by the end of the nine-hour flight, they understood each other perfectly.