The above line is from the chapter "The Man Who Knew Too Much" by the author, Alexander Baron. In the given situation, the men are on a walk. The Professor had accompanied them.  Suddenly, the sound of a drone was heard.It was a sunny day and the men could not see directly and identify the aircraft, due to the glare of the sun. So, the men started debating about the type of aircraft it was. They had always felt that the identification of aircraft was their strongest suit. But, their notions came shattering down when the Professor had aptly identified the aircraft as without looking up. This was not good for the ego of the men and thry felt quite deflated.