The kids were on their way to Disneyworld, paid for by Gary Sinise's charity The Snowball Express.

The video was filmed on Saturday at the Nashville Airport by traveler Jen Tringale, who captioned it with this:

 

I witnessed an international airport come to a complete stop today ... At the Nashville airport I walked out into the concourse to this scene @americanairlines was flying a plane full of children who had lost a parent in combat to Disneyworld on an all expenses paid trip and they threw a party for them at the gate❤️But when they announced them over the loud speaker and they lined up to board the plane the whole airport literally stopped and sang the national anthem with military present in salute. Most every person standing around, myself included was bawling at the sight of these kids and spouses who have paid so great a price for our country. To see all of this at Christmas time was so humbling. Seeing the general public in an airport stand still to honor these kids was simply beauitful. 

This happens every December - the Snowball Express flies gold-star children to Disneyworld on an all-expenses-paid trip with American Airlines.