Asking consumers (or yourself) why something happens or why they do something seems to be a legitimate question. It's your approach to the question behind it: "what shall we do?"
However, you probably will not get insightful answers. I suggest the question should be slightly tweaked to make it work better. I call it "why +". (I could have called it somehow less disgusting, but it helps me remember the technique.)
Why+ works like this: you put another meaningful word behind "why", that points somewhere and guides the respondent's attention.
Why not at the airport?
Isn't this magic?
I love this kind of things...