I drive the kids everywhere so when we are actually all together as a family I want him to drive. Then I can read email and Facebook.
My husband usually drives when we go places together. He just plain likes to drive more than I do. I would rather look around at the sights or read.
When we are going places together, he usually drives at my request. I have to commute during the week (he takes the bus to work) and I get really sick of driving in traffic, so I ask him to drive most of the other times.
Depending on how far this woman had just driven to get to the airport, she may have just needed a break. I don't know about everyone else, but my butt gets pretty sore after driving for awhile.
If we are going anywhere new, he drives. He has a terrible sense of direction and if he navigates, we get lost. On long trips he always drives, because I am selfish and usually have a handwork project (I sew) going and want to work on it. And he is nice like that.