For months after the attacks many of the city's firehouses and police stations were draped in black and purple mourning bunting. A kind of veil had dropped on the city and even as we slowly returned to the rhythm of our days, there was not any tangible feeling of normal. Not when "normal" included fighter jets making their frequent passes over New York City's airspace. And yet, there was a kind of learned comfort that came with the sound of those protective aircraft. As if you could trick yourself into feeling slightly less helpless when bolstered by their fierce speed screaming overhead.