Damn, without a doubt, the introduction X-40 Nightmare with the Brain-Computer Interface (BCI) system born from the Darkness of Enigma (D.O.E.) project is what bridges the gap to *AC3*. Years later, that would lead to the creation of the dangerous Opto-Neuron system, which Rena Hirose would operate in the X-47 Night Raven it's insane!
The aircraft itself, X-40 is a fitting for Moon 11 bearing the "nightmare" she brought among others, her people, and herself. And it's the reason why Cope wanted to set her free from her "nightmares" by ending her life in the hands of his co-pilot to guide her to the afterlife that she longed for. I feel sorry for the late Rex to see her close friend (or girlfriend) being that way. I wonder if he persuade her to live life to fly together in the land where she won't need to fight? Will it change anything if he was alive?