Hmmm. This does not strike me as a difficult question! My idea of a difficult interview question is:
"What are you worst at?"
The answer of "I'm a pefectionist" usually provides an early exit.
The next stumbler is:
"What have you screwed up in the past?"
If you say "Nothing" then bye bye. LOL!
I would be suprised if these did not find their way into Airline interviews in some for or another.