We knew that the parts needed for the upgrade would be hard to get, and perhaps even more challenging to implement with the old tech we're riding on today. Eventhough UNADT (United Nation Alien Defence Technology) had suffered great losses they still had the tech, and, somehow the know-how to reconstruct and implement these brilliant machines. Nephilim technology is really tech from another dimension, it doesn't share or resemblance anything of how we build or engineer machines. Their scientist must really be from a different world where gravity is long tamed and mastered.

Anyway, the system, once unpacked, was defective but working, now we just have to find a crew with the balls to actually fly these crafts.