The opening scene of Knight and Day shows the two main characters "accidentally" bumping into each other twice, in the Wichita airport. The city of Wichita, and the state of Kansas, are mentioned many times throughout the film. Not surprising, considering the movie was previously titled simply Wichita, during production (source).
However, as a native Wichitan, and someone who has flown into and out of the Wichita airport many times, I can say with absolute certainty that the opening scene of this movie was not actually filmed in Wichita. The Wichita airport has exactly zero escalators, despite the dozens shown in the film.
Where was this scene actually filmed? And why wasn't it filmed in Wichita, Kansas?