Some background, so it's common for planes to have 6 seats/row with an aisle in between. Three on one side and three on another. Also, the aisle is so narrow, it's pretty much single file. Airlines use a dumbass system where it costs money if you want to select your own seat, so if you don't pay, you are randomly scattered around the plane at any open seat. It's common for families to let the chips fall where they lie and when the family gets separated, they ask to swap so they can all sit together.