In the movie 13 days, as part of the strategy to gain more information about the cuban missile sites, low level flights are authorized by the president.
what does kenny o'donnell tell the pilot he must not do and why?

The right answer for the question that is being asked and shown above is that: "1. Don't get shot down; 2. Don't report that you were shot down. The U.S. would have to respond with war." That is what Kenny O'Donnell tell the pilot he must not do and the reason.