I feel like an idiot. I completely forgot about those pieces of art released back during SDCC and the Hawkeye cover and the Shield agents cover had the bottom of the Helicarrier on them.
Responsibility, Duty, Honor these are not
mere virtues to which we must aspire
they're Essential...to every soldier
....to every King.
Coulson, "If the details of this gets out, the operation would be complimized"