An unfortunate letter, but as the original posters here and to the newspaper showed you can't fly a formation of FJs over a big city without a lot of people noticing, even early in the morning. The reason here isn't something that most people would guess, and perhaps a little pre-publicity by the base might have helped. Tricky.
I wonder if the correspondents saw them after they'd closed up after doing the Missing Man formation. That's unambiguous... and never fails to make me unsafe to speak for a while afterwards.
R