Firstly, the men are clearly heard laughing and joking about the hijackings, a very strange thing to do in the face of an all out terrorist suicide attack.

One officer says “That’s it, I’m not flying with United or American any more,” amongst the laughter another responds “I never thought I would have wished for ValuJet to come back.”

One of the officers later states “I’m glad I’m not flying today,” to which the answer is, “Don’t worry Jim, we’ll carjack you on the way home.” Two minutes later the men are talking about stock they own.

Another key part of the audio comes as the officers attempt to find a transponder signal for flight 175. One officer states “I’m looking for a squawk” — military jargon for a transponder signal from the aircraft — A second officer remarks “We have smart terrorists today, they are not giving them a chance to squawk”.

What does this officer mean?

His use of the word “today” indicates that terrorist hijackings of airliners are a daily occurrence. In this sense it is more likely that he is referring to previous drills of hijackings, which we know were ongoing in the days and weeks leading up to the attacks on 9/11, as well as on the actual day.

Furthermore, who is the “they” that the officer refers to? Are the terrorists “they”? — ie “They (the terrorists) are not giving them (the aircraft/pilots) the chance to squawk”.

Or are “they” another group, military officers running a drill perhaps, that
are not giving the fictional terrorists the chance to squawk, thus making the drill harder?

It is not so hard to imagine, given that multiple personnel at NORAD and NEADS are on record as having admitted they originally thought the attacks were part of the drill.

Furthermore, according to Larry Arnold, who was the commanding general of NORAD’s Continental U.S. Region, the Vigilant Guardian exercise was only canceled after the second World Trade Center tower was hit at 9:03 a.m., a timeline which dovetails exactly with the above clip.